Revelation 15:3

And they sung the song of Moses the servant of God, and the song of the Lamb, saying: Great and wonderful are thy works, Lord God Almighty; just and true are thy ways, thou King of saints.

Romans 12:2

And be not conformed to this age, but be transformed by the renewing of your mind, that you may learn what the will of God is the good, and the acceptable, and the 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 this age, but be transformed by the renewing of your mind, that you may learn what the will of God is the good, and the acceptable, and the perfect.
Revelation 15:3
And they sung the song of Moses the servant of God, and the song of the Lamb, saying: Great and wonderful are thy works, Lord God Almighty; just and true are thy ways, thou King of saints.