Praise the Lord with harp - For a description of the “harp,” see the notes at Isaiah 5:12.
Sing unto him with the psaltery - For the meaning of this word, also, see the notes at Isaiah 5:12, where the word is rendered “viol.”
And an instrument of ten strings - The word “and” is supplied here by the translators as if, in this place, a third instrument was referred to, distinct from the harp and the psaltery. The more correct rendering, however, would be, “a psaltery (or lyre) of ten strings.” The same construction occurs in Psalms 144:9. In Psalms 92:3, however, the two words are separately used as denoting different instruments. The “lyre” or psaltery was probably not always made with the same number of strings, and it would seem that the one that was made of “ten” strings had something special about it as an instrument of uncommon sweetness or power. Hence, it is particularly designated here; and the idea is that the instruments of especial power and sweetness should be on this occasion employed in the service of God.