John Calvin Commentary Matthew 16:2

"But he answered and said unto them, When it is evening, ye say, [It will be] fair weather: for the heaven is red." — Matthew 16:2 (ASV)

About the beginning of the evening. By these words, Christ reminds them that his power had been sufficiently shown, so that they must have recognized the time of their visitation (Luke 19:44), if they had not willingly shut their eyes and refused to admit the clearest light.

The comparison he uses is beautiful and highly appropriate. For, though the appearance of the sky changes, so that sometimes a storm unexpectedly arises, and sometimes good weather appears when it was not expected, yet the lessons from nature are sufficient to enable people to predict from signs whether the day will be fair or cloudy.

Christ therefore asks why they do not recognize the kingdom of God when it is made known by signs just as clear. For this proved clearly that they were excessively preoccupied with earthly and temporary advantages, cared little about anything related to the heavenly and spiritual life, and were blinded not so much by mistake as by willful malice.