Mark 8:14

11 and the Pharisees came forth, and began to dispute with him, seeking from him a sign from the heaven, tempting him;

12 and having sighed deeply in his spirit, he saith, `Why doth this generation seek after a sign? Verily I say to you, no sign shall be given to this generation.`

13 And having left them, having entered again into the boat, he went away to the other side;

14 and they forgot to take loaves, and except one loaf they had nothing with them in the boat,

15 and he was charging them, saying, `Take heed, beware of the leaven of the Pharisees, and of the leaven of Herod,`

16 and they were reasoning with one another, saying -- `Because we have no loaves.`

17 And Jesus having known, saith to them, `Why do ye reason, because ye have no loaves? do ye not yet perceive, nor understand, yet have ye your heart hardened?