Matthew 16:15

The Pharisees also with the Sadducees came, and tempting desired him that he would shew them a sign from heaven.

He answered and said unto them, When it is evening, ye say, It will be fair weather: for the sky is red.

And in the morning, It will be foul weather to day: for the sky is red and lowring. O ye hypocrites, ye can discern the face of the sky; but can ye not discern the signs of the times?

A wicked and adulterous generation seeketh after a sign; and there shall no sign be given unto it, but the sign of the prophet Jonas. And he left them, and departed.