Revelation 15:3

And they were singing the song of Moses, the slave of God, and the song of the Lamb: "Great and wonderful are your works, Lord God, Almighty One; upright and true your ways, O King of the ages.

Romans 12:2

Stop living in accordance with the customs of this world, but by the new ideals that mold your minds continue to transform yourselves, so as to find and follow God's will; that is, what is good, well-pleasing to Him, 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
Stop living in accordance with the customs of this world, but by the new ideals that mold your minds continue to transform yourselves, so as to find and follow God's will; that is, what is good, well-pleasing to Him, and perfect.
Revelation 15:3
And they were singing the song of Moses, the slave of God, and the song of the Lamb: "Great and wonderful are your works, Lord God, Almighty One; upright and true your ways, O King of the ages.