Mark 8:10-13

And immediately he got into the boat with his disciples and went to the district of Dalmanutha. The Pharisees came and began to argue with him, seeking from him a sign from heaven to test him. And he sighed deeply in his spirit and said, “Why does this generation seek a sign? Truly, I say to you, no sign will be given to this generation.” And he left them, got into the boat again, and went to the other side.