Problem: The psalmist commands, “Worship Him, all you gods.” Yet the Bible elsewhere insists there is only one God (Deut. 6:4).
Solution: First of all, there is no other God, but there are many gods. There is only one true God, but there are many false gods. Indeed, Paul declares that there are demons behind false gods (1 Cor. 10:20). And one day even the demons will bow before the true and living God and confess that He is Lord (Phil. 2:10).
Furthermore, good angels are sometimes called “gods” (elohim) in the Bible (Ps. 8:5; cf. Heb. 2:7). This verse (Ps. 97:7) could be a command for the angels to worship God, as they are so commanded in Psalm 148:2: “Praise Him, all His angels.”