The paragraph consisting of this and Matthew 16:3 is omitted by many good manuscripts, probably owing to its similarity to the passage in Matthew 12:38. These verses are most probably genuine; and they certainly could not have been foisted into the text from Luke 12:54-56.
The circumstances are too different, and the variations too marked, to make such interpolation probable. When it is evening. The Pharisees had demanded a sign from heaven; Jesus points to the western glow in the sky, and taunts them with being ready enough to read the signs of the weather, but slow to interpret proofs of more important circumstances.
He does not, in the case of these mixed cavillers, argue from Scripture, but from the natural world, and he points out that, had they eyes to see and a mind to discern, they might mark tokens in historical events, in the moral and spiritual world, which attested his Messiahship as clearly as any specially given sign from heaven.
Ye say, It will be fair weather ( εὐδία). Probably an exclamation, Ye say, Fair weather! Rabbinical schools made a point of teaching weather lore; prognostications on this subject were greatly in vogue, and the rains of the coming year were annually foretold.
On such meteorological observations, we may refer to Virgil, 'Georg,' 1.425, etc.; and Pliny, 'Nat. Hist.,' 18.35 and 78.