Mark 8:10-13 NIV

10 he got into the boat with his disciples and went to the region of Dalmanutha.
11 The Pharisees came and began to question Jesus. To test him, they asked him for a sign from heaven.1

References for Mark 8:11

12 He sighed deeply2 and said, "Why does this generation ask for a miraculous sign? I tell you the truth, no sign will be given to it."

References for Mark 8:12

13 Then he left them, got back into the boat and crossed to the other side.