Leaven in Israel!

God initially separated His people Israel from Egypt at the Passover that they might be pure and holy in His presence. The spiritual leaders of Israel were at that time charged with keeping God's people apart from all worldliness and wickedness. Wickedness was typified as "leaven" in the Jewish religious feasts. But by Jesus' day, the Jews had lapsed into disobedience, hypocrisy, and unbelief (hence Jesus' caution about their "yeast"). Jesus taught His disciples to beware of leaven because, if left unchecked, it is always ruinous to God's people, causing them not to differ at all from the world.