Acts 2:18

On προφητεύσουσιν (Acts 2:18; Joel 2:28 LXX): From προφητεύω (prophēteuō), Doric προφᾱτεύω, fut. -εύσω, aor. 1 ἐπροφήτευσα, “to act as a προφήτης” — in classical usage, an interpreter or spokesman for a deity, not limited to foretelling the future (Pind. Pyth. fr. 150; Eur. Ion 369, 413).

In the Septuagint it renders the Hebrew passive Niphal נבא (nāvāʾ), “to prophesy". Thus προφητεύσουσιν may be glossed more precisely as “they will serve as prophets” or “they will act as God’s spokespeople,” rather than merely “predict the future.”

Cf. נבאו – When the Word Speaks You: The Aonic Nature of Hebrew Prophecy in the Niphal