So let us keep our feast, not with old yeast nor with the yeast of vice and wickedness, but with the bread of purity and truth without the yeast.

How is it that you do not understand that I did not speak to you about bread, when I said, keep on guarding yourselves against the yeast of the Pharisees and the Sadducees?"

Then they understood that He meant, guard yourselves not against yeast for bread, but against the teaching of the Pharisees and the Sadducees.