Proverbs 25:3 in the King James Version
The heaven for height, and the earth for depth, and the heart of kings is unsearchable.
Context
2 It is the glory of God to conceal a thing, but the glory of kings is to search out a matter.
3 As the heavens for height, and the earth for depth, so the hearts of kings are unsearchable.
4 Take away the dross from the silver, and material comes out for the refiner.