Acts 2:20

"Before that great and notable day of the Lord come." For be not confident, he means to say, because at present you sin with impunity. For these things are the prelude of a certain great and dreadful day. Do you see how he made their souls to quake and melt within them, and turned their laughter into pleading for acquittal? For if these things are the prelude of that day, it follows that the extreme of danger is impending.

"Blood and fire, and vapor of smoke." Observe how he describes the capture. "The sun shall be turned into darkness, and the moon into blood." This results from the internal affection of the sufferers. It is said, indeed, that many such phenomena actually did occur in the sky, as Josephus attests. At the same time the Apostle strikes fear into them, by reminding them of the darkness which had lately occurred, and leading them to expect things to come.

The worst to come first; namely, the inhabitants to be taken, and then the city to be razed and burnt. Then he dwelt upon the metaphor, bringing before the eyes of the hearers the overthrow and the taking. "The sun shall be turned into darkness, and the moon into blood." What means, the moon turned into blood? It denotes the excess of the slaughter. The language is fraught with helpless dismay.