Psalms 71:22

I will also praise thee with the psaltery,.... An instrument of music; [See comments on Psalms 33:2];

[even] thy truth, O my God; that is, his faithfulness in fulfilling his promises, which is never suffered to fail;

unto thee will I sing with the harp; another instrument of music; and both typical of the spiritual melody in the heart, which believers make in praising the Lord, when they sing the Lamb's new song; see

Revelation 14:2;

O thou Holy One of Israel; the God of Israel, that dwells among them, and sanctifies them; and who is essentially and perfectly holy in himself, and in all his ways and works; the remembrance of which occasions praise and thankfulness, Psalms 97:12.