Jamieson, Fausset and Brown on Psalms 97:7

7. Idolaters are utterly put to shame, for if angels must worship Him, how much more those who worshipped them.

all ye gods--literally, "all ye angels" (Psa 8:5; 138:1; He 1:6; 2:7). Paul quotes, not as a prophecy, but as language used in regard to the Lord Jehovah, who in the Old Testament theophania is the second person of the Godhead.