Serve the LORD with gladness: come before his presence with singing.
Read Chapter 100
Augustine of Hippo
10. "O serve the Lord with gladness" (ver. 2): he addresseth you, whoever ye are who endure all things in love, and rejoice in hope. "Serve the Lord," not in the bitterness of murmuring, but in the "gladness of love." "Come before His presence with rejoicing." It is easy to rejoice outwardly: rejoice before the presence of God. Let not the tongue be too joyful: let the conscience be joyful. "Come before His presence with a song."
Not. St. Jerome seems to have read lu for lo, and translates, "and we are his "which Houbigant follows. But the Vulgate gives a very necessary instruction, as some might perhaps forget that God preserves their life every instant, (Berthier) and some have foolishly imagined, that the collection of things might give existence, or be eternal. (Berthier)