Mark 8:10-13

And straightway he entered into the boat with his disciples, and came into the parts of Dalmanutha. And the Pharisees came forth, and began to question with him, seeking of him a sign from heaven, trying him. And he sighed deeply in his spirit, and saith, Why doth this generation seek a sign? verily I say unto you, There shall no sign be given unto this generation. And he left them, and again entering into the boat departed to the other side.