Verse 1
Psalms 98:1. O sing unto the Lord a new song — See on Psalms 96:1. For he hath done marvellous things — The work of our redemption and salvation by Christ is a work of wonder. If we take a view of all the steps of it, from the contrivance of it before all time to the consummation of it, and its everlasting consequences when time shall be no more, we shall say, God has in it done marvellous things; it is all his doing, and it is marvellous in our eyes. His right hand, &c., hath gotten him the victory — God, by his own only power, hath overcome all difficulties and enemies, and hath, in spite of all opposition, raised Christ from the dead, and set him upon his throne, and propagated his kingdom in the world.

Verse 2-3
Psalms 98:2-3. The Lord hath made known his salvation — The redemption of the world by the Messiah; which was hitherto reserved as a secret among the Jews, yea, was not thoroughly known by most of the Jews themselves. His righteousness hath he openly showed — Either his faithfulness in accomplishing this great promise of sending the Messiah; or his goodness and mercy, often termed his righteousness, or God’s method of justifying sinners, and making them righteous through faith in Christ, continually called the righteousness of God in the New Testament. He hath remembered his mercy and his truth — He hath now actually given that mercy which he had promised to the Israelites. All the ends of the earth — All its inhabitants, from one end to another; have seen the salvation of our God — It has been published, and plainly discovered to them, not in types and shadows, as under the law, but written as with a sun-beam, and exhibited openly, that he who runs may read it.

Verses 4-9
Psalms 98:4-9. Make a joyful noise, &c. — Because you all now partake of the same privileges with the Jews, join with them in worshipping and praising God. Sing unto the Lord with a harp — Here again, as in Psalms 92:3, the worship of the New Testament is described in phrases taken from the rites of the Old. “The psalmist, beholding in spirit the accomplishment of the promises, the advent of Christ, and the glory of his kingdom, thinks it criminal in any creature to be silent: he bids the whole earth break forth into joy, and exult in God her Saviour, with every token of gratitude and thankfulness.” He even calls upon “the inanimate parts of creation to bear their parts in the new song, and to fill up the universal chorus of praise.” He bids the sea roar, as men in triumph make a loud and vehement noise, and the floods to clap their hands, as men do in token of delight and approbation, while the hills, in like manner, resound their joy. Before the Lord, for he cometh, &c. — Here we have “the subject of this general joy, as before in Psalms 96:13, namely, the coming of the Messiah to reform the world, to execute judgment upon the wicked, and to establish a kingdom of righteousness upon the earth. We expect his second advent to restore all things, to judge the world, to condemn his enemies, and to begin his glorious reign. Then shall heaven and earth rejoice, and the joy of the redeemed shall be full.” — Horne.