Acts 2:19

“And I will show wonders in heaven above, etc.] The word above is not in Joel, nor in the Syriac version here, as neither the word “beneath”, in the next clause. This may refer either to the appearance of angels, and of an extraordinary star at the birth of Christ; or rather to comets and blazing stars, and particularly to that comet which, in the form of a flaming sword, hung over Jerusalem, and the forms of armies in the heavens engaged together, which were seen before, and portended the destruction of that city f115: and signs in the earth beneath; meaning either the miracles done by Christ, and his apostles, on earth; or those surprising events in Judea and in Jerusalem, a flame was seen…”

“I will show wonders, &c.--referring to the signs which were to precede the destruction of Jerusalem (see on Luk 21:25-28).”

“I will show wonders - Literally, “I will give signs” - δώσω τέρατα dōsō terata. The word in the Hebrew, מופתים mowpatiym, means properly “prodigies; wonderful occurrences; miracles performed by God or his messengers,” Exodus 4:21; Exodus 7:3, Exodus 7:9; Exodus 11:9; Deuteronomy 4:34, etc. It is the common word to denote a miracle in the Old Testament. Here it means, however, a portentous appearance, a prodigy, a remarkable occurrence. It is commonly joined in the New Testament with the word “signs” - “signs and wonders,” Matthew 24:24; Mark 13:22; John 4:48. In these places it does not of necessity mean miracles, but unusual and remarkable appearances. Here it is used to mean great and…”

“And I will show prodigies in heaven above, and signs on earth beneath - Great revelations of grace are usually attended with great judgments on those who reject it. In heaven - Treated of, Act 2:20. On earth - Described in this verse. Such signs were those mentioned, Act 2:22, before the passion of Christ; which are so mentioned as to include also those at the very time of the passion and resurrection, at the destruction of Jerusalem, and at the end of the world. Terrible indeed were those prodigies in particular which preceded the destruction of Jerusalem: such as the flaming sword hanging over the city, and the fiery comet pointing down upon it for a year; the light that shone upon the…”

“Joe 2:30, Joe 2:31; Zep 1:14-18; Mal 4:1-6 Acts 2:20”