Every year around Passover, the same questions surface: What counts as leaven? Is it yeast? Baking soda? Beer? Heat?
But the more I’ve studied this, the more I’ve come to believe we are often asking the wrong question.
The issue is not primarily what technically qualifies as leaven, it’s that we’ve become disconnected from what leaven is and what it does.
Without that understanding, we tend to default into rule-keeping, surface-level compliance, and, at times, judgment without depth.
Passover invites us into something far deeper than technical arguments and surface-level judgments.
Scripture commands:
Exodus 12:15 “For seven days you are to eat matzah; on the first day remove the chametz from your houses.”
The word chametz (חָמֵץ) literally carries the idea of souring, fermentation, decay over time.
In the ancient world, leaven was not purchased, it was preserved. A small portion of yesterday’s dough was set aside and allowed to ferment. And once the fermentation had taken hold, it was then introduced into new dough.
So every loaf of leavened bread was new dough shaped by old fermentation.
This is the key.
Leaven works slowly. It does not appear overnight. It develops over time, often unnoticed, until eventually it defines the whole.
This is why Scripture consistently uses leaven as a metaphor. Because it mirrors the way influence works in our lives:
These processes are slow, which is why we often cannot identify the exact moment our lives made the turn. Yet over time, the whole life is affected by the gradual shift.
Galatians 5:9 A little leaven leavens the whole batch of dough.
This is why Paul’s warning is so sobering. He is not merely saying that a small amount of sin exists somewhere in the dough. He is saying that small, tolerated influence does not stay small. It works through the whole thing until the whole thing begins to carry its nature.
That is what makes leaven such a powerful image. It is not loud. It is not immediate. It does not announce itself as corruption. It simply remains, spreads, and reshapes whatever it is given access to.
And perhaps most importantly, leaven must be fed to remain alive. Which leads to a troubling question:
What are we still feeding?
At Passover, Abba gives a radical command: Remove it. Completely.
Not manage it. Not reduce it. Not control it.
Remove it.
Why? Because Israel was not just leaving Egypt geographically. They were leaving its patterns, its mindset, and its influence.
Passover is not just an exit. It is a reset. Abba is saying, “A new season is upon you. Do not bring old fermentation into new life.”
During this time, instead of leavened bread, Israel is commanded to eat matzah (מַצָּה): Unleavened bread.
No fermentation. No delay. No inherited influence. Just flour, water, and fire.
If leavened bread is sour, matzah would be considered “unsoured”. It has not been corrupted. It represents sincerity, purity, and simplicity.
Paul even tells us,
1 Corinthians 5:8 …let us celebrate… with the matzah of purity and truth.
On the other side of the coin, however, it most certainly is not “purity and truth”.
Yeshua warns us,
Matthew 16:6 “Watch out… beware of the leaven of the Pharisees.”
Luke 12:1 “The leaven of the Pharisees… is hypocrisy.”
This is critical. Leaven is not just sin in general. It is systemic influence, especially when it is inherited, preserved, and unquestioned.
Now, the Pharisees were not inventing something new, they were maintaining something old. They served a system built over generations with many interpretations and traditions that had strayed from the Ways of God.
Layer upon layer. Just like sourdough starter.
As we can see, the danger of leaven is not just that it spreads. It is that it becomes normal. Over time, what is inherited begins to feel authoritative and unquestionable. Left long enough, it even begins to feel sacred.
But Yeshua warns against this very thing as well:
Mark 7:8 “You abandon God’s commandment and hold onto human tradition.”
Leaven becomes most dangerous when it no longer feels like leaven.
And this is what Yeshua wanted to expose.
In Matthew 5-7, Yeshua is not abolishing the Torah, He is removing the leaven from it.
He is not lowering the standard. He is removing the contamination that allowed people to appear obedient while remaining unchanged within.
“You have heard it said…”
“But I tell you…”
He is stripping away external performance and inherited distortion, and restoring heart-level obedience and internal purity.
He is restoring sincerity before God.
Matthew 5:8 “Blessed are the pure in heart, for they will see God.”
That word “pure” carries the idea of unmixed, undiluted, without contamination.
In other words, unleavened.
Now, leaven always tends to produce a very specific outcome: hypocrisy.
Because over time the outside is maintained while the inside is neglected. So you get appearance without substance. In that condition, people can appear obedient without actually being transformed. Worse still, we can end up with religion without relationship.
Matthew 23:27 “You are like whitewashed tombs… beautiful on the outside but full… within.”
This is fermented faith.
Against all of this, Yeshua makes a staggering claim:
John 6:51 “I am the living bread that came down from heaven.”
This is the turning point. This is the contrast Passover has been pointing toward all along. Abba does not merely call His people to remove what is sour. He calls them to receive what is pure. He does not simply expose the old fermentation, He gives Bread from Heaven that has not been touched by Egypt, hypocrisy, tradition, pride, or decay.
But this also means the question of leaven is not locked in the past. It is not merely an ancient Passover concern or a first-century warning against the Pharisees. If leaven is influence that spreads, then we should expect it to become more dangerous when deception multiplies, lawlessness increases, and whole systems become comfortable with corruption.
This is exactly what Yeshua says will happen near the end of the age.
Yeshua warns that leaven will intensify over time.
Matthew 24:12 “Because of increased lawlessness, many people’s love will grow cold.”
This is fermentation language.
Something spreads.
Something increases.
Something alters the whole.
In the Last Days, deception will increase and lawlessness will spread. The truth will become even more diluted. Even within religious systems.
That does not mean every tradition is evil, nor does it mean every denomination is intentionally rebellious. But it does mean inherited systems must be tested. Every generation has to ask whether it is preserving the Word of God or preserving the fermentation of men who came before them.
This is where Passover becomes deeply personal. It is easy to condemn Egypt. It is easy to criticize the Pharisees. It is easy to point at denominations, institutions, and religious systems. But the harder question is whether we are willing to let Abba search what has been preserved in us.
Because when the end of this age comes upon us, we are all going to be faced with the same question.
When the end of this age comes upon us, we are all going to be faced with the same question.
The issue will not be: “Are you religious?”
The issue will be: “Are you pure?”
Not how much you inherited or how much you performed. But whether your life is leavened or unleavened.
This leads to a necessary conclusion: Faith cannot be inherited. It must be pursued.
Others can teach, guide, and disciple, but they cannot seek Abba for you.
Jeremiah 29:13 “You will seek me and find me when you seek me with all your heart.”
There is no substitute for opening the Word yourself.
There is no substitute for seeking His face yourself.
There is no substitute for walking with Him personally.
Because real life with our God is never inherited, it is pursued.
So Passover is not just about leaving Egypt. It is leaving everything Egypt left in you.
It is breaking inherited patterns and removing unseen influence. Greater still, it is refusing old fermentation and learning to live from something entirely new.
Pharaoh represents external bondage.
The Pharisees reveal internal bondage.
Passover addresses both.
Abba says, “leave where you were and leave what has been shaping you.”
Do not bring yesterday’s fermentation into today’s life.
Instead, receive the Bread from Heaven.
Not shaped by the past… Not inherited through tradition…
But given by God.
This is the true movement from sour to pure. Not merely removing bread from the house, but allowing Abba to remove Egypt, hypocrisy, inherited distortion, and old fermentation from the heart.
Passover is not an invitation to appear clean for a week. It is an invitation to become a new lump -- sincere, pure, and shaped by the Bread that came down from Heaven.
So the question is not only, “What counts as leaven?”
The deeper question is, “What has been leavening me?”
And once Abba shows us, the command is still the same:
Remove it.