Science of Sainthood
The Old Testament Origin of Pentecost that Explains the Birth of the Catholic Church

The Old Testament Origin of Pentecost that Explains the Birth of the Catholic Church

pentecost podcast May 26, 2023

Not everything in the New Testament is actually "new". Many people don't realize that the feast of Pentecost didn't start with the descent of the Holy Spirit in Acts 2. In fact, it began all the way back at the foot of Mount Sinai in the book of Exodus.

And once you understand what happened back at Sinai, you start to more fully understand why we celebrate Pentecost not just as the coming of the Holy Spirit, but also the birth of the Catholic Church.

God bless and enjoy!


P.S. The incredible audio Bible you hear is the Truth and Life Audio Bible that you can find at Check it out!



Welcome to the Art of Catholic podcast. I’m Matthew Leonard.

Pentecost is upon us and I thought I’d reach back into the Art of Catholic vault and pull out one of the more popular episodes I’ve done which goes into the amazing Old Testament backstory of this great feast that most people aren’t aware of. But once you see the it, what happens in Jerusalem two thousand years ago makes a whole lot more sense. And it will deepen your personal celebration of this great event.

Welcome to a special Pentecost edition of the Art of Catholic podcast, my friends. This is going to be a very important, and dare I say, illuminating show. I want to get into the amazing backstory of what is going on in the passage we just heard from the book of Acts. And once you hear it all, you’ll have a much clearer understanding of everything going on at this incredible event we read about in Scripture, which we’re celebrating on this Sunday. As with so many other things in the New Testament, the events of Pentecost didn’t just fall out of the sky, so to speak. It wasn’t a random event. It is connected very deeply to the Old Testament…to a very particular event in the Old Testament, as a matter of fact. And within that event there are a lot of really connections to the book of Acts that fill in a lot of blanks and help make sense of what we’re about to celebrate.

There is a ton to get to, so let’s get it on.

Let’s start with the fact that Pentecost takes place 9 days after the Ascension of Jesus, which is described in Acts 1 and we celebrated last Sunday. These days the feast day – at least in the US – not sure what it’s like in other countries – has been moved to the Sunday before Pentecost, I suppose to make it easier for people. I think it loses a lot of its significance when we do that.

We used to all celebrate Ascension Thursday. And that’s important because Pentecost takes place 9 days after the Ascension. It’s not totally for sure, but a lot of people point to the 9 day period between the Ascension and Pentecost as the origin of novenas as there is no history of 9 day celebrations in Judaism. The Romans had them, but not the Jews. Anyway, Novena or novem, is latin for “ninefold” or “nine”. So it is a devotion consisting of prayers or something similar for nine successive days.

And just a quick note about the Ascension. Realize that the "going up" of Christ isn't physical per se, just like his descent into hell wasn't a physical going down. Yes, heaven must be a place in some sense because the body of Christ and Mary are both there. But we also know that their bodies are not subject to space and time as we are now. Christ was walking through walls and eating solid food. So heaven isn’t a physical place, at least as we conceive of it. I suppose that’s one of the reasons Paul says, “Eye has not seen nor ear heard what God has prepared for those who love him”.  Heaven is beyond our present capabilities and understanding.

So there’s a sense in which the Ascension of Christ is the removal of the veil of reality. Christ begins to show us what it’s all about as the veil between the heavenly and earthly is torn down. The humiliation of the Cross leads to the exaltation of our Lord. This is the pattern we are to follow. In order to share in the resurrection and Ascension of our Lord, we have to first share in his suffering. That is why humility is so important. The Ascension is also the penetration of humanity into divinity. The God-man rises into the family of the Trinity, so to speak. And it sets up the release the Holy Spirit nine days later. 

So anyway, nine days after the Ascension of our Lord all heaven breaks loose and the Holy Spirit descends. And you heard the description in the opening cut which I got from the Truth and Life Dramatized Audio Bible which is a professionally produced and acted audio of Scripture featuring the voices of people like Sean Astin, Stacy Keach, and Brian Cox. If you’re interested – and you should be because it’s really amazing – there’s an app that has the whole thing and you can listen to it on any smart device. If you’re interested, go to Once again, my thanks to Mike Stark for giving me permission to use the audio.

Okay…back to the story… it’s a pretty crazy scene at Pentecost. There’s a sound like rushing wind which filled the house where the Apostles were hanging out and praying. Now think about that…because we just breeze right over this stuff…no pun intended. But you can be in a pretty heavy windstorm  - like those of us in the Midwest have experienced – but it doesn’t fill your house. I was in a 103 mile an hour storm when I lived right on Lake Michigan and my house wasn’t filled with the sound of rushing wind. Yes, my house was made of bricks and not even the big bad wolf could blow it down, but seriously, this was no ordinary wind. It’s incredibly powerful. Crazy powerful. Then all of the sudden tongues of fire appear over them all and they start speaking other tongues, or languages.

Now why were they speaking other languages? What’s the point? Well, we read in Acts 2:5 and following that there were people there from “every nation under earth”. And all of them heard the Disciples talking in their native tongue and describing the mighty works of God. So it’s a crazy scene. Again, I think we don’t really appreciate how wild all of this was because we’ve heard these stories so often they lose their power.

It’s no wonder that some of the people present thought the Apostles were drunk. There were so many languages being spoken they were thinking “these guys must be tipsy.” The problem with that theory is that was about 9am in the morning. You gotta be hard core to be drunk at that time. Not only that, the Jewish pilgrims for Pentecost normally fasted the morning of Pentecost. It was a time of penance, not party time.

Now this brings us to an interesting point. A lot of Catholics don’t realize that the feast of Pentecost didn’t begin in Acts 2 when the Holy Spirit came. It’s not a Christian feast, per se…at least not originally.

It was Jewish feast that had been around a long, long time. The word Pentecost means “fifty” in Greek and it was celebrated 50 days after Passover. It was one of three pilgrim feasts that required Jewish men to make a trip to Jerusalem. It was a harvest festival sometimes called the Feast of Weeks, that eventually took on more theological significance. What significance, you ask? Well, the Feast of Pentecost was a celebration commemorating when the people of Israel became the people of God , receiving the law of the covenant at the foot of Mt. Sinai way back in the time of Moses.

Remember that Moses led the Israelites out of slavery in Egypt, crossed the Red Sea and ended up at the foot of Mt Sinai. And about 50 days later, it was there that they swore a sacred covenant oath with God that he would be there God and they would be his people. This is where the Israelites received the 10 Commandments, the Law of the Covenant. But when you read the story, you start to see it was a pretty nutty scene itself. The events at Sinai were pretty scary in a lot of ways.

In Exodus 19 the Israelites arrive at Sinai and God tells Moses on the mountain that the people are supposed ritually purify themselves because he’s coming in 3 days. And he does. Let me read starting at verse 16:

On the morning of the third day there were thunders and lightnings, and a thick cloud upon the mountain, and a very loud trumpet blast, so that all the people who were in the camp trembled17 Then Moses brought the people out of the camp to meet God; and they took their stand at the foot of the mountain. 18 And Mount Sinai was wrapped in smoke, because the Lord descended upon it in fire; and the smoke of it went up like the smoke of a kiln, and the whole mountain quaked greatly19 And as the sound of the trumpet grew louder and louder, Moses spoke, and God answered him in thunder. 20 And the Lord came down upon Mount Sinai, to the top of the mountain; and the Lord called Moses to the top of the mountain, and Moses went up. 

Again, we breeze over this stuff…God descended upon the mountain in fire! Things were quaking. There was thunder and lightning! This wasn’t like the consecration at Mass where things happen a little more calmly. Nobody was distracted. Nobody was looking around wondering if they were going to make it home for the game in time. God came down from heaven in a very visible way and it was awesome!

Imagine if you were hanging there at the foot of the mountain. Especially since the Israelites were supposed to have ritually purified themselves so as to step foot on the mountain and it appears they didn’t do so because none of them head up the mountain. That’s a whole other issue we don’t have time for, but it still boggles my mind. This is the people who have just witnessed the destruction of the entire Egyptian army in the Red Sea after they walked through it on dry ground. And before that, they’d seen the 10 plagues decimate Egypt in a bunch of other ways. And yet they refuse to follow the Lord’s command to purify themselves and get ready for his arrival…not that any of us would ever ignore what the Lord asks us to do.

Anyway… Moses and Aaron go up and Moses receives the 10 Commandments.

Okay. A few things I want to point out here to tie these events and Pentecost in Acts 2 together and fill in some blanks of the story. So what are the parallels between what the scene at Sinai and Jerusalem in Acts 2?

First of allBoth take place on mountains. Mt Sinai is the scene of the first. Pentecost in Acts 2 takes place on Mt. Zion…In Jerusalem.

Both events have serious weather patterns: Sinai has thunder and lightning, smoke and fire, an earthquake. Again, the Lord actually descends in fire in Exodus 19:16 and appears like a “devouring fire” on top of the mountain in Exodus 24:17. Even for people who witnessed a lof of miracles, this had to be pretty awe inspiring.

A point of interest here is that the word “thunder” as used in the book of Exodus can be translated as “voices” – “qol” in Hebrew. So it is the sound of voices or the voice of God they hear on the mountain. And to  say it’s not a demure voice would be the mildest of understatements. In fact, this is the same word used to describe the sound made when God descends into the Garden of Eden after the original sin of Adam and Eve. Again, it’s not just any old voice. If you look at Psalm 29 you see the “qol” or voice of the Lord,  “breaks the cedars…flashes forth flames of fire…shakes the wilderness…makes the oaks to whirl and strips the forests bare.”

The thunders or voice of the Lord is intense! That’s the same thing going on in Acts 2 with the rushing wind. And think about this…what do the people in Jerusalem hear? The voices of the Apostles proclaiming the glory of the Lord in different languages…after what…after the tongues of fire descend upon them in a parallel way as to the descending of fire in Exodus 19.

What else do we have?

  • At Sinai the people were kept away from the fire on the mountain because they had not purified themselves. But at Pentecost in Acts, the fire comes into their midst through the Apostles. They don’t have to fear this time, especially since Christ has fulfilled the terms of the blood covenant they broke at Sinai (and all the other covenants). The curse of death has been lifted.
  • At Sinai the Israelites received a law written on stone – the Ten Commandments. At Pentecost the people received a law written on the human heart. The prophet Jeremiah said, “Behold, the days are coming, says the Lord, when I will make a new covenant…not like the covenant which I made with their fathers when I took them by the hand to bring them out of the land of Egypt…But this is the covenant which I will make with the house of Israel after those days, says the Lord: I will put my law within them, and I will write it upon their hearts.” St. Thomas Aquinas says that the law of the New Covenant is nothing other than the grace of the Holy Spirit, which is exactly what showed up at Pentecost.

And while it’s not a parallel to Sinai, it’s interesting to note that all the languages being spoken by the Apostles which are understood by the people, is the reverse of what happened back in Genesis 11 at the Tower of Babel where all the languages were confused and everyone dispersed. Genesis 10 is called the Table of Nations and it lists all the different peoples that came out of the lines of the three sons of Noah – Ham, Shem, and Japheth. And then we see in Genesis 11 how wicked they are and want to make a name for themselves and build the tower trying to reach heaven. (There’s a lot going on here we don’t have time for – name is literally Shem…they want to make a Shem for themselves, something that has all kinds of meaning, Shem being the faithful first-born of Noah.) Anyway, they try and build the tower and God confuses their language and all the peoples of the world are scattered. Now at Pentecost they can all understand the Gospel and are being brought back together.

Okay, one more parallel I want to point out here, and I think I saved the best for last. At least, this one was the coolest one to me when I learned it. At Sinai, after the people receive the law of the Lord, they swear a covenant with God. Now those of you who have ever been through a Journey Through Scripture series know that a covenant is how families are created. That’s what they do. That’s the purpose of a covenant. When God swears his covenant with us, it’s to make us his family. The whole story of the Bible is a story of covenants as God is getting us back into the family, which Adam got kicked out of.  So God makes covenants with Adam, Noah, Abraham, Moses and David as the family of God gets bigger and bigger again. These Old Testament covenants are finally fulfilled in the New Covenant of Jesus Christ where finally the family of God isn’t only dictated by natural bloodlines, but through the blood of Jesus Christ. The whole Bible is about family life. It’s about us getting into the family of God for which we were made. The Trinity itself is a covenant family.

This is why we have covenant language all through Scripture, our prayers, the liturgy…everywhere. Covenants make families because God himself is a family. As JPII said… “God in his deepest mystery is not a solitude, but a family because he has within him Fatherhood, Sonship and the essence of the family which is love.” I don’t have the time to get totally into all of this right now, but realize that we still do this today. We still swear covenants. A marriage is a covenant. Think about it. You take two people who are unrelated, they swear a covenant, and viola…they’re a family.

God is our Father because he has sworn a covenant with us. God has been swearing a series of covenants with humanity from the beginning. All the covenants come to completion and fulfillment in the New Covenant sacrifice of Jesus Christ which is designed to make us sons and daughters of God, members of the covenant family. That’s what we’re made for. That’s who God designed us to be.

Okay, why am I telling you all of this. Because it’s going to help explain an event that troubles a lot of people.

When the Israelites arrive at Sinai, they eventually swear a covenant with God. He says they will be his people if they follow the commands he has given them. They receive the law of the covenant and all the people say “yeah”, we’re good with this.” “All that the Lord has spoken we will do.” Then comes a covenant oath ceremony where Moses sacrifices two oxen and sprinkles half of the blood on the altar and half of the blood on the people. This is a very serious ceremony that often accompanied the swearing of covenants. The sacrifice of the animal symbolized what would happen if someone broke the covenant. Because covenants were very serious business. We break contracts all day long and don’t’ think anything of it. Covenants go way beyond contracts. They’re sworn in God’s name and have serious consequences when broken (i.e. death.) So the people would declare their fidelity and then show they meant it through sacrifice.

In other words, the people are placing themselves under blood oath. They are basically saying, let it be done to us what was done to the oxen if we break this covenant.” Again, the penalty for breaking covenant was death. Everybody understood this.

Moses then goes back up Sinai into the fire of God. And we all know what happens. The people lose heart thinking Moses has been consumed by God and they have Aaron construct a golden calf to worship and commit terrible sexual sin around it. (Apis – the bull god they’re worshipping is an Egyptian god of fertility…Ex 32:6…)

So 40 days after they swear a blood oath to God, they break it. Moses comes down the mountain, sees what’s going on and says “Who is on the Lord’s side?” His kinsmen, the Levites, come to his side and he says "slay the idolaters". And we read that 3000 people die that day. Now that’s pretty heavy and it troubles a lot of people. What kind of a God does this? Most don’t understand that according to the terms of the covenant, they all should have died. They all swore a blood oath that they would not worship other gods, and then a little more than a month later that’s exactly what they’re doing. But only 3,000 die.

I’ve heard a lot of speculation about who the 3,000 were. I've heard some people speculate that the 3000 were in particular the first-born sons and that maybe they fell under special judgment because the first born sons were the ones who were actually liberated...they were saved and redeemed, so to speak in the 10th plague when the Angel of Death passed over their houses. That's where the "passover" comes from in the 10th plague and the Israelites were saved by offering an unblemished lamb and they eat it. And if they didn't do that...they didn't kill the unblemished lamb, spread it's blood on the doorpost and then eat the meat that night then the firstborn would die. So some people have said that maybe it's the firstborn who died at the Golden Calf. I don't know. It's not important to us right now.

What I want to point out is this. As I said earlier, at the foot of Sinai, the people of Israel become the people of God. They break their covenant, 3,000 of them are put to death. Now fast forward to Pentecost. A similar scene plays out with all the parallels we’ve mentioned. But instead of calling out the sin of the people and then having to kill the idolaters as Moses did, Peter preaches the first homily in the history of the Church and the people are “cut to the heart” says Acts 2:37.

“Brethren, what shall we do? And Peter said to them, “Repent, and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins; and you shall receive the gift of the Holy Spirit. 39 For the promise is to you and to your children and to all that are far off, every one whom the Lord our God calls to him.” 40 And he testified with many other words and exhorted them, saying, “Save yourselves from this crooked generation.” 41 So those who received his word were baptized, and there were added that day about three thousand souls. 42 And they devoted themselves to the apostles’ teaching and fellowship, to the breaking of bread and the prayers.

Did you notice how many people came into the church that day? 3,000. In other words, the 3,000 lost through the broken covenant at the foot of Sinai in the old Israel is restored to the New Israel – the Church - because of the New Covenant of Jesus Christ. This is the birth of the new people of God. What was dead has been brought back to life through the power of the Holy Spirit – through the sacraments. I love this stuff!

Why did I say through the sacraments? Because Peter tells them what they have to do to be saved-  “Repent and be baptized.” And of course, look at what the people devoted themselves to: the apostles’ teaching and fellowship, to the breaking of bread and the prayers. “Breaking the bread” is early church language for the Eucharist. They were baptized, celebrated Mass and prayed. The same things we are to do today.

So there you have it. The backstory of Pentecost in the book of Acts is the scene at Sinai way back at the birth of Israel as the people of God. We are the new people of God. We are the New Israel, the restored and transformed kingdom of God in the New Covenant of Jesus Christ! Thanks be to God for the Holy Spirit! He brings us life. He manifests God in our presence. He continues the power of the resurrected and ascended Christ in our lives.

Remember that the Disciples didn’t want Jesus to leave. And we can all understand that. We’d all feel the same way. But Jesus tells them they want the Holy Spirit to come. It is the Spirit that gives life. The Holy Spirit brings Christ to us through the sacraments. He guides in the life of prayer. He draws us closer to our Lord so that we can fulfill our destiny as children of God. Don’t ever stop asking for the Holy Spirit.

I hope you guys enjoyed it. There’s a whole lot more to be said about the Holy Spirit. And if you want to dive more deeply into the 3rd Person of the Most Holy Trinity – and why wouldn’t you? - there’s a course on the Gifts of the Spirit in the Science Of Sainthood, the online platform where I teach the ins and outs of Catholic spirituality for regular Catholics.

It’s dynamic, step by step spiritual guidance and formation that will lead you more deeply than ever into the relationship with Christ that you crave. It’s literally the path to sainthood laid out by all the spiritual giants of our faith like Teresa of Avila, John of the Cross, Francis de Sales, and so many others. I’ve taken about 2000 years of Catholic spiritual teaching and boiled it all down to bite sized, beautiful video courses so that you can move into a divine intimacy with the Lord that will take your breath away.  And you can check that out at

That’s it for now, but Lord willing, there is a lot more to come. But for now, let’s close with our theme verse from Romans 12:12 – “Rejoice in hope. Endure in affliction. Persevere in prayer.”


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