We might also understand this saying, “When it is evening, ye say, It will be fair weather, for the sky is red,” in this way, By the blood of Christ’s passion at His first coming, indulgence of sin is given. “And in the morning, It will be foul weather today, for the sky is red and lowring;” that is, at His second coming He will come with fire before Him.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Quaest Ev., i, 20