Yeast is mentioned several times throughout the Bible, and it carries important symbolic meaning. As Christians seeking to understand God’s Word, it’s important that we study the scriptures closely to discern what yeast represents. In this post, we’ll take a comprehensive look at the biblical references to yeast and what they mean for believers today.
In the Bible, yeast is consistently used as a metaphor for the permeating and spreading nature of sin. Jesus Himself warns believers to “beware of the leaven of the Pharisees” (Luke 12:1 NKJV), and the apostle Paul exhorted the Corinthians to “Therefore purge out the old leaven, that you may be a new lump, since you truly are unleavened” (1 Corinthians 5:7 NKJV). It’s clear that yeast is often associated with sin, evil, and corruption in Scripture.
Understanding why requires digging deeper into the properties of yeast itself. Yeast is an agent that causes bread dough to rise and grow in size as it spreads throughout the lump of dough. In the ancient world, yeast was a mysterious substance – people didn’t understand the science behind fermentation as we do today. So to them, it seemed yeast had almost magical properties in the way it could infiltrate and alter dough.
This explains why yeast became an apt metaphor and symbol for how sin operates. Sin starts small, in the same way yeast is mixed into dough in tiny measures. But if left unchecked and allowed to spread, sin, like yeast, will swell and distort its host, changing its very nature. Sin is almost “infectious” in this way – even a small amount can impact an entire being.
As we explore the biblical references, keep this metaphor in mind. Yeast is used to illustrate how sin can subtly but profoundly permeate our hearts, minds, and lives if we don’t guard against it.
Old Testament References
The Old Testament contains a few significant references to yeast that lay the foundation for Jesus’ later teachings.
In giving instructions for offerings made to the Lord, yeast or leaven is prohibited:
You shall not offer the bread of your God from any of these if it is leavened; for you shall burn no leaven, nor any honey, as an offering made by fire to the Lord. (Leviticus 2:11 NKJV)
And for the wave offering to accompany peace offerings:
‘All the offerings of your grain offerings you shall season with salt; you shall not allow the salt of the covenant of your God to be lacking from your grain offering. With all your offerings you shall offer salt. ‘If you offer a grain offering of your firstfruits to the Lord, you shall offer for the grain offering of your firstfruits green heads of grain roasted on the fire, grain beaten from full heads. And you shall put oil on it, and lay frankincense on it. It is a grain offering. Then the priest shall burn the memorial portion: part of its beaten grain and part of its oil, with all the frankincense, as an offering made by fire to the Lord. (Leviticus 2:13-16 NKJV)
And speaking about first fruits:
‘No grain offering which you bring to the Lord shall be made with leaven, for you shall burn no leaven nor any honey in any offering to the Lord made by fire. (Leviticus 2:11 NKJV)
So in the context of offerings to God, yeast was strictly prohibited. This helps establish the yeast/sin connection – just as sin has no place in offerings made in the temple, yeast was not permitted in the actual offerings. Yeast symbolized impurity.
This symbolism is made even more explicit in the instructions for the Passover feast:
‘Seven days you shall eat unleavened bread. On the first day you shall remove leaven from your houses. For whoever eats leavened bread from the first day until the seventh day, that person shall be cut off from Israel. On the first day there shall be a holy convocation, and on the seventh day there shall be a holy convocation for you. No manner of work shall be done on them; but that which everyone must eat—that only may be prepared by you. So you shall observe the Feast of Unleavened Bread, for on this same day I will have brought your armies out of the land of Egypt. Therefore you shall observe this day throughout your generations as an everlasting ordinance. In the first month, on the fourteenth day of the month at evening, you shall eat unleavened bread, until the twenty-first day of the month at evening. For seven days no leaven shall be found in your houses, since whoever eats what is leavened, that same person shall be cut off from the congregation of Israel, whether he is a stranger or a native of the land. You shall eat nothing leavened; in all your dwellings you shall eat unleavened bread.’” (Exodus 12:15-20 NKJV)
The Feast of Unleavened Bread was deeply symbolic of Israel’s exodus from slavery in Egypt. God had delivered His people, so in commemoration, His people were to root out sin from their lives and homes,represented by cleansing out all yeast. For seven days, the Israelites were to eat bread without yeast to remind them of God’s rescue and to re-consecrate themselves to lives of holiness.
Again, this demonstrates how yeast was clearly symbolic of impurity, evil, and sin in the Old Testament. Just as Israel was redeemed and brought into right relationship with God, leaven was banished.
Finally, we see a wisdom reference to yeast in Proverbs:
Take away the dross from silver, And it will go to the silversmith for jewelry. Take away the wicked from before the king, And his throne will be established in righteousness. (Proverbs 25:4-5 NKJV)
This verse compares yeast to “dross” – the impurities mixed in with silver that must be removed to purify the precious metal. Once again, yeast is something that must be removed to leave only what is precious behind.
Jesus’ Teachings on Yeast
Building upon these Old Testament foundations, Jesus takes up the metaphor of yeast several times in His teachings.
Beware the Yeast of the Pharisees
In Luke’s gospel, Jesus says:
Beware of the leaven of the Pharisees, which is hypocrisy. For there is nothing covered that will not be revealed, nor hidden that will not be known. (Luke 12:1-2 NKJV)
Here, Jesus explicitly connects yeast to the hypocrisy of the religious elite of the day. The Pharisees appeared righteous on the outside, but inwardly harbored pride, greed, and cruelty. Jesus warned the disciples not to allow the subtle, permeating influence of hypocrisy infect their hearts as it had the Pharisees.
Even though the Pharisees were respected religious leaders, Jesus knew the yeast of hypocrisy distorted their witness and ministry. He cautions His followers not to fall into the same trap.
The Yeast of the Sadducees
A similar warning is issued in Matthew and Mark’s gospel about the yeast of the Sadducees:
Then they understood that He did not tell them to beware of the leaven of bread, but of the doctrine of the Pharisees and Sadducees. (Matthew 16:12 NKJV)
While the Pharisees were known for hypocrisy and legalism, the Sadducees tolerated sin and denied foundational doctrines like the resurrection. Jesus warns His disciples against both errors – hypocrisy and laxity – using the metaphor of yeast.
The Kingdom Parables
Finally, in Matthew and Luke, Jesus tells parables likening the kingdom of heaven to yeast:
He spoke another parable to them: “The kingdom of heaven is like leaven, which a woman took and hid in three measures of meal till it was all leavened.” (Matthew 13:33 NKJV)
To what shall I liken the kingdom of God? It is like leaven, which a woman took and hid in three measures of meal till it was all leavened.” (Luke 13:20-21 NKJV)
At first glance, this seems contradictory to the other passages where yeast is clearly symbolic of evil. However, when interpreted properly, these parables are consistent. Jesus is showing how the kingdom starts small but spreads rapidly throughout the world. Yeast depicts the infectious, exponential growth of God’s kingdom through the gospel. Sin may seem pervasive, but the power of Christ’s redeeming work will reach more people and places than we can imagine.
So in these parables, yeast illustrates the permeating power of the gospel for conversion, not the permeating power of sin for corruption. The symbolic meaning remains the same; Jesus is just applying it differently to show how the gospel can spread rapidly in people’s hearts and the world like yeast in dough.
Teachings in the Epistles
Building upon Christ’s teachings, the New Testament epistles continue to use yeast as a metaphor for sin.
1 Corinthians 5
Paul rebukes the Corinthian church for tolerating sexual immorality in their midst:
Your glorying is not good. Do you not know that a little leaven leavens the whole lump? Therefore purge out the old leaven, that you may be a new lump, since you truly are unleavened. For indeed Christ, our Passover, was sacrificed for us. Therefore let us keep the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth. (1 Corinthians 5:6-8 NKJV)
Like Christ, Paul urges the church to remove the yeast of sin from their fellowship, just as the Israelites removed yeast from their homes during Passover. Failure to do so would allow sin to spread. Paul wants the church to live in purity, which is impossible if they tolerate the “yeast” of sexual immorality.
The context here is church discipline – removing unrepentant sinners from membership and fellowship. But the principle applies more broadly to personal holiness – we must regularly examine our hearts and remove any sin that could corrode our witness and relationship with Christ.
In a similar vein, Paul writes to the Galatians:
You ran well. Who hindered you from obeying the truth? This persuasion does not come from Him who calls you. A little leaven leavens the whole lump. (Galatians 5:7-9 NKJV)
The Galatians were being influenced by false teachers who taught salvation comes through the law, not grace. Paul says this heresy is like yeast, corrupting the gospel of grace. Unless rooted out, these small distortions would eventually destroy the truth of the gospel in the Galatian church.
So again, yeast represents dangerous influences that can seem small at first but lead to the decay of sound doctrine. Guarding against false teaching is imperative to prevent the yeast of error from creeping in.
In surveying the biblical evidence, these are the key truths that emerge about what yeast symbolizes:
- Yeast represents the permeating, infectious nature of sin. Like yeast spreads through dough, sin subtly spreads through hearts, homes, churches, and communities if left unchecked.
- Yeast was prohibited in Old Testament offerings and feasts. Yeast represents impurity, which has no place in worship or dedication to God.
- Jesus used yeast to illustrate the hypocrisy of the Pharisees, the laxity of the Sadducees, and the infectiveness of the gospel. Depending on the context, yeast could symbolize how sin or the gospel permeate and spread.
- The epistles continue this metaphorical use of yeast. Yeast depicts sin the church must remove, and false teachings the church must guard against. Both will lead believers astray if tolerated.
As modern disciples, being aware of what yeast symbolizes in Scripture helps us be vigilant against sin and false teaching. We must examine our hearts and congregations to identify and remove the “yeast” of hypocrisy, immorality, legalism, and heresy. And we must allow the “yeast” of the gospel to spread, transforming more hearts and lives through the good news of Christ.
The biblical imagery of yeast is a powerful visual reminder to pursue personal holiness and doctrinal purity. May we all heed its message, so we remain faithful witnesses to our unleavened Savior.