Revelation 19:1

And after these things
After the angel had declared the fall of Babylon, a voice from heaven had called the people of God out of her, and had ordered them to take vengeance on her; after the mournful lamentation of the kings, merchants, and seafaring men; after another voice had called upon the saints to rejoice at her overthrow, and a mighty angel had described the manner of it, and had expressed her ruin in the strongest terms, with the reasons of it, John heard the songs of the righteous, as follow:

I heard a great voice of much people in heaven:
not literally taken, for these are not the innumerable company of angels, who are never called people; nor the spirits of just men made perfect, or the souls of departed saints, but men on earth; wherefore heaven designs the church, as in ( Revelation 18:20 ) and frequently in this book; the people are the same with the 144000 seen with the Lamb on Mount Zion, ( Revelation 14:1 ) and with those on the sea of glass, who had got the victory over the beast, ( Revelation 15:2 ) and are no other than God's covenant people, who are given to Christ, and made willing to be his in the day of his power; and though they are but a seed, a remnant, a small company, when compared with the world and carnal professors; yet are a large body of themselves, especially they will be at this time, when the nation of the Jews shall be born at once, and the fulness of the Gentiles will be brought in: and their voice on this occasion, the downfall of Rome, is said to be "great" partly on account of their number, who will join together in acclamations of praise, and partly on account of their great affection and vehemency of spirit, which will be raised hereby:

saying Alleluia;
an Hebrew word, which signifies "praise ye the Lord". The Jews say ^F14, that the book of Psalms consists of ten sorts of songs, but Hallelujah is the greatest of them, because it comprehends the name (Jehovah) and praise in one word: and it is observable that this word, which is often used in the Psalms, is first used when the Psalmist desires the utter consumption and destruction of sinners and wicked men on earth, and is here taken up by the saints at the destruction of the man of sin and son of perdition; see ( Psalms 104:35 ) and its being an Hebrew word shows that at this time the Jews will be converted, and that Jews and Gentiles will become one church state, and will worship and praise the Lord together; for the word is a call upon the saints to join together in solemn praise and thanksgiving; who is to be praised for the perfections of his nature, for the works of his hands, both of nature and grace; and for his righteous judgments on his and his church's enemies; and this is to be done in concert:

salvation, and glory, and honour, and power, unto the Lord our God:
salvation, temporal, spiritual, and eternal, is of God; "salvation" from antichristian power and tyranny, and from all enemies, and the everlasting salvation of the soul; and the "glory" of it belongs to all the three Persons; they are glorious in themselves, and deserve all glory to be ascribed to them by man, and especially by the saints: "honour" is also their due; God the Father is to be honoured because he is the Father, and the Son is to he honoured as the Father is, and the Holy Spirit is not to be grieved, but to be highly esteemed and valued, and equally with the other two Persons: and "power" belongs to them all, and is seen in the works of creation, redemption, and sanctification.