'Yeast Of The Pharisees' in the Bible

Jesus said to them, "Take heed and beware of the yeast of the Pharisees and Sadducees."

Why is it you don’t understand that when I told you, ‘Beware of the yeast of the Pharisees and Sadducees,’ it wasn’t about bread?”

Then He commanded them: “Watch out! Beware of the yeast of the Pharisees and the yeast of Herod.”

Meanwhile, when a multitude of many thousands had gathered together, so much so that they trampled on each other, he began to tell his disciples first of all, "Beware of the yeast of the Pharisees, which is hypocrisy.