Mark 8:11 Meaning

9And they that had eaten were about four thousand: and he sent them away.

10And straightway he entered into a ship with his disciples, and came into the parts of Dalmanutha.

11And the Pharisees came forth, and began to question with him, seeking of him a sign from heaven, tempting him.

12And he sighed deeply in his spirit, and saith, Why doth this generation seek after a sign? verily I say unto you, There shall no sign be given unto this generation.

13And he left them, and entering into the ship again departed to the other side.