Mark 14:14-21 “Now the disciples had forgotten to take bread, neither had they in the ship with them more than one loaf. And he charged them, saying, Take heed, beware of the leaven of the Pharisees, and of the leaven of Herod. And they reasoned among themselves, saying, It is because we have no bread. And when Jesus knew it, he saith unto them, Why reason ye, because ye have no bread? perceive ye not yet, neither understand? have ye your heart yet hardened? Having eyes, see ye not? and having ears, hear ye not? and do ye not remember? When I brake the five loaves among five thousand, how many baskets full of fragments took ye up? They say unto him, Twelve. And when the seven among four thousand, how many baskets full of fragments took ye up? And they said, Seven. And he said unto them, How is it that ye do not understand?”
Leaven, without any exception whatsoever, is a symbol of sin in the Bible. In Matthew 13:33 and Luke 13:21, for example, leaven refers to the growth of the ecumenical false religious movements of this present dispensation. Those who think that leaven is sometimes a reference to something good, such as the gospel or the church, are simply mistaken. Therefore, when Jesus said, “Beware of the leaven of the Pharisees and of the leaven of Herod,” He was referring to their evil plans and designs. The disciples should have understood it then, and we should understand it now.