Matthew 16:6-12

6 Jesus said to them, “Take heed and beware of the yeast of the Pharisees and Sadducees.”

7 They reasoned among themselves, saying, "We brought no bread."

8 Jesus, perceiving it, said, “Why do you reason among yourselves, you of little faith, 'because you have brought no bread?'  9 Don't you yet perceive, neither remember the five loaves for the five thousand, and how many baskets you took up?  10 Nor the seven loaves for the four thousand, and how many baskets you took up?  11 How is it that you don't perceive that I didn't speak to you concerning bread? But beware of the yeast of the Pharisees and Sadducees.”

12 Then they understood that he didn't tell them to beware of the yeast of bread, but of the teaching of the Pharisees and Sadducees. 

Mark 8:15-21

15 He charged them, saying, “Take heed: beware of the yeast of the Pharisees and the yeast of Herod.”

16 They reasoned with one another, saying, "It's because we have no bread."

17 Jesus, perceiving it, said to them, “Why do you reason that it's because you have no bread? Don't you perceive yet, neither understand? Is your heart still hardened?  18 Having eyes, don't you see? Having ears, don't you hear? Don't you remember?  19 When I broke the five loaves among the five thousand, how many baskets full of broken pieces did you take up?”  They told him, "Twelve."

20 “When the seven loaves fed the four thousand, how many baskets full of broken pieces did you take up?”  They told him, "Seven."

21 He asked them, “Don't you understand, yet?”