Most Bible teachers state that leaven is analogous to sin. Although the two are connected, leaven does not represent sin. Instead, it represents self-righteousness –or simply legalism.
A person living under legalism relies on following rules to be pleasing to God. The rules can be anything –the Ten Commandments, Jesus’ example, avoiding the bad and doing the good found in the New Testament, or just “doing the right thing.” However, that is a life of works –and it is the very opposite of living by faith.
Everything that does not come from faith is sin. (Romans 14:23)
Leaven puffs up a loaf of bread making it appear larger than it would be otherwise. Legalism (or self-righteousness) makes a person measure himself based on his own works. And it leads to a most prideful (puffed up) attitude.
The description of the Passover is found in chapters 12 through 14 of Exodus. In that passage, the two primary things that the people were told to do were slay and eat their lamb; then rid themselves of all leaven –they could not possess it nor could others see them with it.
And for the week beginning at Passover, they were to celebrate the week-long Feast of Unleavened Bread. These were to be an annual reminder that God was trustworthy –for He took them safely out of Egypt. It marked the beginning of the new year –a time of starting over.
All they were to do was follow Him by faith. The lesson to be learned from this feast is that there is nothing that people can do to make their rescue successful. God did all the rescuing. If their good works were involved, then they would have been puffed up –arrogant in their thinking.
But He provided the lamb –Jesus the Lamb of God– to be slain for us. And He provided the unleavened bread –Jesus the Bread of Life. All that we are to do is take Him in –by faith.
His divine power has given us everything we need for life and godliness through our knowledge of Him who called us by His own glory and goodness. (2 Peter 1:3)
The connection of legalism to sin is much like that of a tree to its fruit –one is a natural result of the other. When a person thinks that his efforts help to bring him salvation or even improve his position with God, he is living by works –not faith. That Romans passage above describes this as sin.
Therefore let us keep the Festival, not with the old yeast, the yeast of malice and wickedness, but with bread without yeast, the bread of sincerity and truth. (1 Corinthians 5:8)
When attempting to live life by following rules, people naturally boast and compare themselves to others which breeds malice and wickedness. So let’s live by God’s truth –His word– which explains that the way of life is one of faith.