Proverbs 27:17-19

New Revised Standard Version, Anglicised

¹⁷ Iron sharpens iron,
    and one person sharpens the wits^[a] of another.
¹⁸ Anyone who tends a fig tree will eat its fruit,
    and anyone who takes care of a master will be honoured.
¹⁹ Just as water reflects the face,
    so one human heart reflects another.