Charles Ellicott Commentary Psalms 103:21

"Bless Jehovah, all ye his hosts, Ye ministers of his, that do his pleasure." — Psalms 103:21 (ASV)

Hosts. —There are apparently in the psalmist’s thought three grades of beings in the hierarchy of praise:

1. High angels around the throne.
2. Angelic powers, such as winds, lightnings, etc., specially commissioned to do God’s commands, as in Psalms 104:4.
3. Creation generally. (Compare to Psalms 148)