John Trapp on Psalms 21:1

PSAL. XXI.

VErſ. 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 Davids 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, Pſal. 20. and promiſed ſolemnly to rejoyce in Gods Salvation, &c. verſ. 5. as here is done accordingly. Vow and perform unto the Lord your God: bring preſents, &c. Pſal. 76.11.

And in thy ſalvation] All is Gods. 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 Poſie was, Non nobis Domine; his practiſe was to drive an holy trade between Earth and Heaven, receiving and returning, importing one commodity, and tranſporting another: Prayers and Praiſes were his whole life▪