Revelation 15:1

"And I saw another great and wonderful sign, seven angels having the seven last plagues; for in them is completed the indignation of God." For the wrath of God always strikes the obstinate people with seven plagues, that is, perfectly, as it is said in Leviticus; and these shall be in the last time, when the Church shall have gone out of the midst.

He saw, he says, seven angels having seven plagues. Seven, he says, are the many, the ones prepared against the sinners, by which the wrath of God receives its completion.

Everywhere he uses the number seven, signifying that the injustices done brazenly during the seven days of the present age will be held back by the seven plagues and the seven angels. After these, the future life of the saints, symbolized by the glass sea, will commence.

And I saw another great and marvelous sign in heaven. With the order again restored, about to narrate the same plagues of the final persecution, he wanted the listener to be attentive by saying: A great and marvelous sign.

The seven angels. That is, the Church full of sevenfold grace.

Having the seven last plagues. Because in them the wrath of God is completed, he called them the last: for the wrath of God always strikes the rebellious people with seven plagues, that is, perfect ones, as frequently in Leviticus: And I will strike you with seven plagues (Lev. XXVI). These will be the last when the Church has departed from its midst.