Do not sacrifice [the Passover offering] while you are in possession of chametz (leaven) (Exodus 23:18).
Chametz and matzah have many symbolic explanations. What ever the symbolic meaning may be, one fact cannot be denied. For the few days of Passover, chametz and matzah are antithetical. The Passover seder cannot coexist with chametz. This point is clearly stated in the first of the traditional four questions near the beginning of the Haggadah: "All other nights we eat both chametz and matzah; but this night, only matzah."
Passover tells us that we cannot maintain two opposites, but must make a commitment one way or the other. As Elijah said to the Jews who worshiped idols: "How long will you vacillate between two contradictory ideologies? If Hashem is God, then follow Him. If Baal is god, then follow him" (I Kings 18:21).
People who can take a definite stand can also open themselves to any needed change when they are shown that they are wrong. However, people who constantly vacillate can always find excuses to slither out of improving themselves.
The above verse taught the about-to-be-liberated Israelite and their descendants a vital principle: Do not try to maintain mutually contradictory ideologies.