Proverbs 27:17-21

As iron sharpens iron, So one person sharpens another.

One who tends the fig tree will eat its fruit, And one who cares for his master will be honored.

As in water a face reflects the face, So the heart of a person reflects the person.

Sheol and Abaddon are never satisfied, Nor are the eyes of a person ever satisfied.

The crucible is for silver and the furnace for gold, And each is tested by the praise accorded him.