Leaven is a substance, such as yeast, used as the ingredient in dough or batter to make them rise. In the Scriptures leaven represents an evil influence, be it a lifestyle or a doctrine. We find the first Biblical reference to leaven in Genesis 19:3, where it is mentioned that Lot baked unleavened bread and served it to the two visiting angels, but the subject is addressed in more detail in the Passover chapter in the book of Exodus. The blood of a spotless lamb was to be applied to the doorposts of the house, and the Lord promised that upon seeing the blood, He would pass over them. That very night they were to eat the sacrificed lamb with unleavened bread, and the next day began a seven day festival called the Feast of Unleavened Bread. Unleavened bread was to be eaten the entire week of the festival, and leaven was not even to be seen amongst them. The sacrifice for atonement was not to have any leaven associated with it at all. This, of course, points to the Lamb of God6 whose spotless life paid the price for our sins upon Calvary’s tree. God’s perfect, unleavened sacrifice is the full payment for our sin.
After Calvary, what? Paul tells Christians that we are to keep the feast “with the unleavened bread of sincerity and truth.” Note that Paul identifies the old leaven with sin and commands it be purged out. We must never coddle sin because “a little leaven leavens the whole lump”. In other words, it spreads! Therefore, we are to flee from youthful lusts, even avoiding any appearance of evil (leaven).
Now some evil is less obvious than others. Jesus warned His disciples about religious leaven, typified by the Pharisees, and political leaven, exemplified by Herod. The leaven of the Pharisees was that of religious pretending, looking good on the outside, but rotten within. While we are to seek to restore those overtaken in a fault, we must do so carefully in order to remain “unleavened”.
As the Holy Spirit reveals any areas of leaven in our lives, may we bow our hearts to our forgiving God and receive the cleansing we need. Remember, Jesus came to deliver us from sin that we might be His unleavened church.