Gospel according to Mark 8,11-13
The Pharisees came and started to argue with Jesus. Hoping to embarrass him, they asked for some heavenly sign. Then his spirit was moved. He gave a deep sigh and said, «Why do the people of this present time ask for a sign? Truly, I say to you, no sign shall be given to this people». Then he left them, got into the boat again and went to the other side of the lake.