Psalms 21:1 «To the chief Musician, A Psalm of David. » The king shall joy in thy strength, O LORD; and in thy salvation how greatly shall he rejoice!
Ver. 1. The king shall joy in thy strength] This psalm dependeth upon the former, and is therefore fitly set next unto it. Some call it David's triumphant song of praise, for victory gotten over the Ammonites and Syrians. For that victory it was certainly which he and the people had begged so fervently, Psalms 20:1,9, and promised solemnly to rejoice in God's salvation &c., Psalms 21:5, as here is done accordingly. Vow and perform unto the Lord your God: bring presents, &c., Psalms 76:11 .
And in thy salvation] All is God's. As Joab once sent to David to come and take the honour of the victory over Rabbah of the Ammonites; so dealeth David by the Lord. His posy was, Non nobis, Domine; not by us, O Lord, his practice was to drive a holy trade between earth and heaven, receiving and returning, importing one commodity and transporting another: prayers and praises were his whole life.