A.T. Robertson Commentary Revelation 15:1

"And I saw another sign in heaven, great and marvellous, seven angels having seven plagues, [which are] the last, for in them is finished the wrath of God." — Revelation 15:1 (ASV)

Another sign in heaven (αλλο σημειον εν τω ουρανω). Looking back to 12:1,3, after the series intervening. The Seven Bowls are parallel with the Seven Seals (ch. Revelation 6) and the Seven Trumpets (chapters Re 8-11), but there is an even closer connection with chapters Re 12-14, "the drama of the long conflict between the church and the world" (Swete).

Great and marvellous (μεγα κα θαυμαστον). Θαυμαστος is an old verbal adjective (from θαυμαζω, to wonder) and is already in Mt 21:42. The wonder extends to the end of this vision or sign (16:21).

Seven angels (αγγελους επτα). Accusative case in apposition with σημειον after ειδον. Cf. 8:2.

Which are the last (τας εσχατας). "Seven plagues the last." As in 21:9, "the final cycle of such visitations" (Swete).

Is finished (ετελεσθη). Proleptic prophetic first aorist passive indicative of τελεω as in 10:7. The number seven seems particularly appropriate here for finality and completeness.