Matthew 16:1-4 New American Bible (Revised Edition) (NABRE)
The Demand for a Sign. 1 [a]The Pharisees and Sadducees came and, to test him, asked him to show them a sign from heaven. 2 [b]He said to them in reply, “[In the evening you say, ‘Tomorrow will be fair, for the sky is red’; 3 and, in the morning, ‘Today will be stormy, for the sky is red and threatening.’ You know how to judge the appearance of the sky, but you cannot judge the signs of the times.] 4 An evil and unfaithful generation seeks a sign, but no sign will be given it except the sign of Jonah.”[c] Then he left them and went away.
Luke 11:29-30 New American Bible (Revised Edition) (NABRE)
29 While still more people gathered in the crowd, he said to them, “This generation is an evil generation; it seeks a sign, but no sign will be given it, except the sign of Jonah. 30 Just as Jonah became a sign to the Ninevites, so will the Son of Man be to this generation.