14-16 This day shall be for you a memorial day, and you shall keep it as a feast to the Lord; throughout your generations, as a statute for ever, you shall keep it as a feast.” For seven days you shall eat unleavened bread. On the first day you shall remove leaven out of your houses, for if anyone eats what is leavened, from the first day until the seventh day, that person shall be cut off from Israel. On the first day you shall hold a holy assembly, and on the seventh day a holy assembly. No work shall be done on those days. But what everyone needs to eat, that alone may be prepared by you.

17 And you shall observe the Feast of Unleavened Bread, for on this very day I brought your hosts out of the land of Egypt. Therefore you shall observe this day, throughout your generations, as a statute for ever. 18-20 In the first month, from 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 is to be found in your houses. If anyone eats what is leavened, that person will be cut off from the congregation of Israel, whether he is a sojourner or a native of the land. You shall eat nothing leavened; in all your dwelling places you shall eat unleavened bread.” Exodus 12:14-20 English Standard Version

At the start of this chapter we were told that the Lord said to Moses and Aaron in the land of Egypt, “This month shall be for you the beginning of months. It shall be the first month of the year for you.” It was the month called Abib, which begins towards the end of March and extends into April of our calendar. They were to set aside an unblemished lamb, and on the 14th day of the month it would be killed and eaten. Some blood from the lamb was to be put on the doorposts and lintels of their homes. The result was that when God struck down the firstborn of man and beast in Egypt, He would pass over the homes where the blood was seen. This event would lead to the annual memorial feast, still celebrated in Jewish homes today, of Passover. But what would another name for this feast be. (vs 17)

We see that the festival would last for a whole week, from the 14th to 21st day of the month, and during that time only bread made without leaven (yeast) could be eaten. In fact, all leaven was to be removed from their homes throughout that week. Hence the festival being called the Feast of Unleavened Bread. And they needed to take this command very seriously because anyone who ignored it was to be excommunicated from the congregation of Israel. It was like being put out of the family of God. So what was this command all about?

Some time later, when Moses gave more teaching about the Passover, he said: “Don't eat the Passover with bread made with yeast, but for seven days eat unleavened bread, the bread of affliction, because you left Egypt in haste - so that all the days of your life you may remember the time of your departure from Egypt.” (Deuteronomy 16:3) The unleavened bread was to remind them of how they had been afflicted in Egypt, and the haste with which they escaped. There had been no time to wait for the dough to rise.

But, speaking through the apostle Paul, the Holy Spirit gives us another insight into the significance of the absence of leaven. Paul was dealing with a congregation who were treating a seriously sinful incident in the Church far too lightly, and even in a boasting way. So he says to them: “Your boasting is not good. Don’t you know that a little yeast leavens the whole batch of dough? Get rid of the old yeast, so that you may be a new unleavened batch - as you really are. For Christ, our Passover lamb, has been sacrificed. Therefore let us keep the Festival, not with the old bread leavened with malice and wickedness, but with the unleavened bread of sincerity and truth.” (1 Corinthians 5:6-8)

The spreading nature of yeast is a very good picture of the spreading nature of sin. Even sins that 'look small' in our sight, can lead an individual, or a whole congregation, into more sin. Individuals and congregations can be corrupted by not dealing with the first signs of disobedience to God. Just as the Israelites were told to 'remove leaven out of your houses' – so Christians are called to 'get rid of the old leaven' of wickedness and malice. May that be true of us.