Matthew 16:1-4

1Now the Pharisees and Sadducees came up, and testing Jesus [to get something to use against Him], they asked Him to show them a sign from heaven [which would support His divine authority].

2But He replied to them, “When it is evening, you say, ‘It will be fair weather, for the sky is red.’

3And in the morning, ‘It will be stormy today, for the sky is red and has a threatening look.’ You know how to interpret the appearance of the sky, but cannot interpret the signs of the times?

4An evil and [morally] unfaithful generation craves a [miraculous] sign; but no sign will be given to it, except the sign of [the prophet] Jonah.” Then He left them and went away.