Sing unto the Lord a new song. The call for a "new song" is based upon the ground that the mercy vouchsafed was a "new" one (see Isaiah 42:9). The expression is frequent in the Psalms (Psalms 33:3; Psalms 96:1; Psalms 98:1; Psalms 144:9; Psalms 149:1).
His praise from the end of the earth; i.e. "let his praise be sung by all the inhabitants of the earth to its remotest bounds." The sea. Sea and land are called upon equally to proclaim God's praise; the sea, "and its fulness" (margin)—those who frequent it in ships, and those who dwell on its shores and islands.
The last clause, "the isles and the inhabitants thereof," is exegetical of the preceding one—" all that is therein."