Proverbs 27:17-23

Iron sharpeneth iron; So a man sharpeneth the countenance of his friend. Whoso keepeth the fig tree shall eat the fruit thereof: So he that waiteth on his master shall be honoured. As in water face answereth to face, So the heart of man to man. Hell and destruction are never full; So the eyes of man are never satisfied. As the fining pot for silver, and the furnace for gold; So is a man to his praise. Though thou shouldest bray a fool in a mortar among wheat with a pestle, Yet will not his foolishness depart from him. Be thou diligent to know the state of thy flocks, And look well to thy herds.