Matthew 16:6

In the mean time, when there were gathered together an innumerable multitude of people, insomuch that they trode one upon another, he began to say unto his disciples first of all, Beware ye of the leaven of the Pharisees, which is hypocrisy.

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.

A little leaven leaveneth the whole lump.

No meat offering, which ye shall bring unto the LORD, shall be made with leaven: for ye shall burn no leaven, nor any honey, in any offering of the LORD made by fire.

And he charged them, saying, Take heed, beware of the leaven of the Pharisees, and of the leaven of Herod.

And he said unto them, Take heed, and beware of covetousness: for a man’s life consisteth not in the abundance of the things which he possesseth.