Leaven is repeatedly emphasized in the Bible. It is mentioned more than 70 times from the time of Abraham to the life of Moses to the histories of the kingdoms to the former prophets, major prophets and minor prophets. Jesus Christ talked about it during His ministry, and He emphasized it on the final night before He was crucified.

Why? Because leaven is a powerful spiritual symbol.

The biblical book that mentions leaven most frequently is Exodus. Exodus 12 records God commanding millions of Israelite slaves in Egypt to keep the Passover, in part by eating lamb, bitter herbs and unleavened bread. The next night, God miraculously freed them, and they joyfully left Egypt. Verse 34 notes that they “took their dough before it was leavened.” Seven days later, with the Egyptian army in pursuit, God miraculously divided the Red Sea, the Israelites walked across the seabed on dry land, and the returning waters destroyed the Egyptians.

God commanded His people to memorialize these events—and their spiritual meaning—by keeping annual observances: Passover at sunset, the Night to Be Much Observed the following sunset, and the feast of Unleavened Bread over the next seven days.

“Seven days shall ye eat unleavened bread; even the first day ye shall put away leaven out of your houses: for whosoever eateth leavened bread from the first day until the seventh day, that soul shall be cut off from Israel. … [F]or in this selfsame day have I brought your armies out of the land of Egypt …” (verses 15, 17).

Jewish believers still keep a form of this observance. But it is actually commanded for God’s Church today. The Apostle Paul wrote to New Testament Christians that “Christ our passover is sacrificed for us; Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth” (1 Corinthians 5:7-8). New Testament Christians keep the feast of Unleavened Bread! (see Acts 20:6).

There is nothing inherently wrong, unhealthy or evil about leavening. But during this unique one-week period, God uses leavening to represent sin. God commands that we get it out of our lives during this time—every last loaf, slice and crumb!

Jesus warned against “the leaven of the Pharisees and of the Sadducees” in Matthew 16. The Apostle Paul focused on leaven in 1 Corinthians 5:6-7: “Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump? Purge out therefore the old leaven ….” The Bible links the way leavening puffs up dough and the way sin spreads and permeates our life. It only takes a pinch of leavening to raise an entire loaf—and it only takes a single compromise to fill our life with sin.

Sin means breaking God’s law of love (1 John 3:4; Romans 13:8-10). It ultimately results in death (Romans 6:23). Every particle of human failure and suffering is caused by breaking God’s law, just as failure and suffering are caused by breaking the laws of biology, chemistry and physics. Let sin into your thinking, and it quickly spreads from one part of your life to another—to another to another. It subtly infuses you with selfishness. It puffs you up with vanity. And it takes God’s miraculous intervention, combined with your effort, to put sin out of your mind and completely keep it out!

Just as with the ancient Israelites, God focuses us on “cleaning house” during the Days of Unleavened Bread: removing every crumb of bread with leavening ingredients like yeast, baking soda and baking powder from our homes, our workplaces, our vehicles and every nook of personal property in between. This symbolizes ridding our lives from every bit of sin and keeping it out. Physical deleavening is no easy task, but neither is getting sin out of our lives. It takes real effort and sweat to deleaven your possessions, just like it is a constant, lifelong battle to remove sin and keep it out when it inevitably begins to creep back in.

However, simply getting the leavening out doesn’t completely fulfill the command in Exodus 12:20. For seven days we not only avoid leavening, but we also eat unleavened bread, representing God’s way of sincerity and truth (1 Corinthians 5:8). That bread symbolizes Jesus Christ Himself—the “bread of life,” the bread we must eat if we are to inherit eternal life (John 6:35, 48). As we ingest that and allow Christ into us, He transforms us into a new and different person. This is another beautiful lesson of the Days of Unleavened Bread.

For God’s people, from Moses and the Israelites to David and the kingdom of Israel to Jesus Christ and His disciples to New Testament Christians through the ages, one of the greatest highlights of the year is the meaningful, exciting, inspiring feast of Unleavened Bread.

To learn more about this annual sacred festival, read Exodus 12-13 and Pagan Holidays—or God’s Holy Days—Which? You can also download a holy day calendar.