2:17

in the last days: In this quote from Joel’s prophecy, Peter under inspiration uses the phrase “in the last days” rather than the expression “after that,” which is used in the original Hebrew and in the Septuagint. (Joe 2:28 [3:1, LXX]) Joel’s prophecy was fulfilled when holy spirit was poured out at Pentecost. Therefore, Peter’s use of the term “the last days” indicates that this special time period had begun and that it would precede “the great and illustrious day of Jehovah.” This “day of Jehovah” would apparently bring “the last days” to their conclusion. (Ac 2:20) Peter was speaking to natural Jews and Jewish proselytes, so his inspired words must have had an initial fulfillment involving them. His statement apparently indicated that the Jews were living in “the last days” of the system of things that had its center of worship in Jerusalem. Earlier, Jesus himself foretold the destruction of Jerusalem and its temple. (Lu 19:41-44; 21:5, 6) That destruction took place in 70 C.E.

my spirit: The Greek word pneuʹma here refers to God’s holy spirit, or active force. At Joe 2:28, quoted here, the corresponding Hebrew word ruʹach is used. Both the Hebrew and the Greek words convey the basic idea of that which is invisible to human sight and gives evidence of force in motion.​—See Glossary, “Spirit.”

every sort of flesh: Or “all sorts (kinds) of people.” Lit., “all flesh.” The Greek word sarx (often rendered “flesh”) is here used of living humans, so “all flesh” would generally refer to all mankind. (See study note on Joh 17:2.) But in this context, the Greek phrase “all flesh” has a more restricted use. God did not pour out his spirit on all humans on earth or even on all humans in Israel, so it does not refer to all humans without exception. Rather, the phrase here refers to all sorts of humans without distinction. God poured out holy spirit on ‘sons and daughters, young men and old men, male slaves and female slaves,’ that is, all sorts of people. (Ac 2:17, 18) A similar use of the Greek word for “all” (pas) is found at 1Ti 2:3, 4, according to which it is God’s will that “all sorts of people should be saved.”​—See study note on Joh 12:32.

prophesy: The Greek term pro·phe·teuʹo literally means “to speak out.” In the Scriptures, it is used of making known messages from a divine source. While it often includes the thought of foretelling the future, the basic meaning of the word is not that of prediction. The Greek word can also refer to identifying a matter by divine revelation. (See study notes on Mt 26:68; Mr 14:65; Lu 22:64.) In this context, holy spirit impelled some to prophesy. By declaring “the magnificent things” that Jehovah had done and would still do, they would serve as spokesmen for the Most High. (Ac 2:11) The Hebrew word for “to prophesy” carries a similar idea. For example, at Ex 7:1, Aaron is referred to as Moses’ “prophet” in the sense that he became Moses’ spokesman, or mouthpiece, rather than in the sense of foretelling future events.

old men: Or “older men; elders.” Here the Greek term pre·sbyʹte·ros likely refers to men of advanced physical age in contrast with the “young men” mentioned earlier in the verse. In other contexts, the same term is used to refer to men holding a position of authority and responsibility in a community or a nation.​—Ac 4:5; 11:30; 14:23; 15:2; 20:17; see study note on Mt 16:21.