7. But--connected with Re 10:6. "There shall be no longer time (that is, delay), but in the days of the voice of the seventh angel, when he is about to (so the Greek) sound his trumpet (so the Greek), then (literally, 'also'; which conjunction often introduces the consequent member of a sentence) the mystery of God is finished," literally, "has been finished"; the prophet regarding the future as certain as if it were past. A, C, Aleph, and Coptic read the past tense (Greek, "etelesthee"). B reads, as English Version, the future tense (Greek, "telesthee"). "should be finished" (compare Re 11:15-18). Sweet consolation to the waiting saints! The seventh trumpet shall be sounded without further delay.
      the mystery of God--the theme of the "little book," and so of the remainder of the Apocalypse. What a grand contrast to the "mystery of iniquity Babylon!" The mystery of God's scheme of redemption, once hidden in God's secret counsel and dimly shadowed forth in types and prophecies, but now more and more clearly revealed according as the Gospel kingdom develops itself, up to its fullest consummation at the end. Then finally His servants shall praise Him most fully, for the glorious consummation of the mystery in having taken to Himself and His saints the kingdom so long usurped by Satan and the ungodly. Thus this verse is an anticipation of Re 11:15-18.
      declared to--Greek, "declared the glad tidings to." "The mystery of God" is the Gospel glad tidings. The office of the prophets is to receive the glad tidings from God, in order to declare them to others. The final consummation is the great theme of the Gospel announced to, and by, the prophets (compare Ga 3:8).

JFB.