Exodus 15:18

The Lord shall reign for ever and ever. Even that same Lord that is spoken of throughout this song, and to whom everything in it is ascribed, and who is no other than the Lord Jesus Christ; his reign began in eternity, when he was set up and anointed as King over God's holy hill of Zion, his church, the elect, who were a kingdom put under his care and charge, and which he will deliver up again one day, complete and perfect: he reigned throughout the whole Old Testament dispensation, and was acknowledged as well as prophesied of as a King; in his state of humiliation he had a kingdom, though not of this world, and upon his ascension to heaven he was made and declared Lord and Christ; and thenceforward his kingdom became very visible in the Gentile world, through the ministration of his word, accompanied by his almighty power; and ever since, more or less, he has ruled by his Spirit and grace in the hearts of many of the children of men, and, ere long, will take upon him his great power, and reign, in a more visible, spiritual, and glorious manner, in the midst of his churches, in the present state of things; and then he will reign with all his saints raised from the dead, for the space of a thousand years on earth, and after that will reign with them for ever in heaven, in the ultimate state of glory and happiness: the reigns of all others are but short, or, however, but for a time, but the reign of Christ is for ever and ever; the reigns of sin, and of Satan, and of death, have an end, but of the government of Christ, and the peace thereof, there will be no end; the reigns of the greatest potentates, emperors, and kings, of cruel and tyrannical princes, such as Pharaoh, are limited to a certain time, as is the reign of antichrist, which when ended, and the saints will have got the victory over him, the song of Moses and the Lamb will be sung; but Christ's kingdom is a […]

Note, It is the unspeakable comfort of all God's faithful subjects, not only that he does reign universally and with an incontestable sovereignty, but that he will reign eternally, and there shall be no end of his dominion. The solemn singing of this song,

The Lord shall reign for ever and ever - This is properly the grand chorus in which all the people joined. The words are expressive of God’s everlasting dominion, not only in the world, but in the Church; not only under the law, but also under the Gospel; not only in time, but through eternity. The original לעלם ועד leolam vaed may be translated, for ever and onward; or, by our very expressive compound term, for Evermore, i.e. for ever and more - not only through time, but also through all duration.