The psalm begins by inviting us to sing a new song to the Lord, for he has done marvelous things. His right hand and his holy arm have worked salvation for him. Verse 2 says the Lord has made known his salvation and revealed his righteousness in the sight of the nations. Verse 3 adds that he has remembered his steadfast love and faithfulness to the house of Israel, and that all the ends of the earth have seen the salvation of our God.
Verses 4-6 call all the earth to make a joyful noise to the Lord. The lyre and the sound of melody are mentioned, along with trumpets and the sound of the horn, to be used before the King, the Lord.
Then all creation joins in: let the sea roar and all that fills it, the world and those who dwell in it, let the rivers clap their hands and the hills sing for joy together before the Lord. The reason is that he comes to judge the earth: he will judge the world with righteousness and the peoples with equity.