Then He charged them, saying, "Take heed, beware of the leaven of the Pharisees and the leaven of Herod."
Mark 8:15
Surrounding context
8:14 Now the disciples had forgotten to take bread, and they did not have more than one loaf with them in the boat.
8:15 Then He charged them, saying, "Take heed, beware of the leaven of the Pharisees and the leaven of Herod."
8:16 And they reasoned among themselves, saying, "It is because we have no bread."