I will sing a new song unto thee, O God,.... The author of his being, the Father of mercies, temporal and spiritual, and therefore to him praise is always due; a new song of praise is to be sung for new mercies; and as these are new every morning, and are renewed day by day, new songs should be sung continually: or this is a song suited to New Testament times, in which all things are become new; there is a new covenant of grace; and a new and living way to the throne of grace; a newly slain sacrifice; redemption newly wrought out, and therefore the new song of redeeming grace must be sung. Arama suggests that this refers to the days of the Messiah; upon a psaltery, and an instrument of ten strings, will I sing praises unto thee; such instruments of music were used in the Old Testament dispensation, and were typical of the hearts of God's people; which are the harps they now strike upon, and where they make melody to the Lord; see Psa 33:2.