It seems strange that the psalmist invokes the heavenly hosts to praise the Lord. Why them? The hosts are identified as the servants who do His will. The Bible gives us glimpses of majestic cherubim, seraphim, and angels in God’s heavenly court, all of whom are eager to do His bidding (Isaiah 6:1-7; Ezekiel 10; Revelation 7:11-12). David says earlier that the love of the Lord is with those who obey His commandments and keep His covenant (vv.17-18). These heavenly hosts are obedient creatures. As faithful servants, they receive the love of God, so the psalmist urges them to praise God.
But what about us, unfaithful sinners who violate His will? Where can we find His steadfast love to praise Him? The answer is in Jesus Christ. In Christ, God forgives all our iniquity, removes our transgressions, adopts us as His children, and bestows His steadfast love upon us (v. 3). Because of Christ’s faithfulness, we are now part of this heavenly choir praising the Lord together with His heavenly hosts. [Yi, Hei Long Jiang, China; second year student]