In the New Testament, yeast is figuratively used for evil or sin, which can penetrate and corrupt our lives if allowed. The way this usually happens is when we compromise in some small area of our life. We say to ourselves, “It really doesn’t matter…it’s just a trivial thing…it’s not hurting anyone.” But just like yeast, it only takes a scant amount to leaven the entire batch…and soon that small unwise action blossoms, showing our vulnerability towards compromise in other areas of our life.