Mark 8: 14 - 21
14 Now they had forgotten to bring bread; and they had only one loaf with them in the boat.
15 And he cautioned them, saying, "Take heed, beware of the leaven of the Pharisees and the leaven of Herod."
16 And they discussed it with one another, saying, "We have no bread."
17 And being aware of it, Jesus said to them, "Why do you discuss the fact that you have no bread? Do you not yet perceive or understand? Are your hearts hardened?
18 Having eyes do you not see, and having ears do you not hear? And do you not remember?
19 When I broke the five loaves for the five thousand, how many baskets full of broken pieces did you take up?" They said to him, "Twelve."
20 "And the seven for the four thousand, how many baskets full of broken pieces did you take up?" And they said to him, "Seven."
21 And he said to them, "Do you not yet understand?"

EWTN