Iron sharpeneth iron; so a man sharpeneth the countenance of his friend.
Proverbs 27:17
King James Version (public domain)
Traditionally attributed to Solomon · c. 10th century BC · King of Israel, renowned for wisdom
Context
15A continual dropping in a very rainy day and a contentious woman are alike.
16Whosoever hideth her hideth the wind, and the ointment of his right hand, which bewrayeth itself.
17Iron sharpeneth iron; so a man sharpeneth the countenance of his friend.
18Whoso keepeth the fig tree shall eat the fruit thereof: so he that waiteth on his master shall be honoured.
19As in water face answereth to face, so the heart of man to man.