Revelation 15:3

and they sung the song of Moses, the servant of God, and the song of the lamb, saying, "great and marvellous are thy works, Lord God almighty; just and true are thy ways, thou king of ages.

Romans 12:2

and be not conformed to the present age: but be ye transformed by the renewing of your mind, that you may perceive what God requires of you is good, and acceptable, and perfect.

Treasury of Scripture Knowledge

Summary

As for God, his way is perfect: the word of the LORD is tried: he is a buckler to all those that trust in him.

Bible References

His way

Romans 12:2
and be not conformed to the present age: but be ye transformed by the renewing of your mind, that you may perceive what God requires of you is good, and acceptable, and perfect.
Revelation 15:3
and they sung the song of Moses, the servant of God, and the song of the lamb, saying, "great and marvellous are thy works, Lord God almighty; just and true are thy ways, thou king of ages.