Mark 8:21 Commentary and Bible Study

The leaven of the Pharisees is a reference to their hypocrisy, but it is also obviously a reference to their teaching, and at the end of this section in the Gospel of Matthew that is explained, so we don't have to think it out. Matthew adds these words of Christ: ‘How is it that ye do not understand that I spake it not to you concerning bread, that ye should beware of the leaven of the Pharisees and of the Sadducees?’ Finally, the disciples grasped his meaning: ‘Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees.’ It was an embarrassing mistake for the disciples and a source of shame that they had not understood before. Christ often used this sort of language, and faith would have ruled out the sort of nonsensical meaning they had come up with.