If the iron be blunt, and he do not whet the edge, then must he put to more strength: but wisdom is profitable to direct.
1 Samuel 13:20
But all the Israelites went down to the Philistines, to sharpen every man his share, and his coulter, and his axe, and his mattock.
Iron sharpeneth iron; so a man sharpeneth the countenance of his friend.
If I whet my glittering sword, and mine hand take hold on judgment; I will render vengeance to mine enemies, and will reward them that hate me.
If he turn not, he will whet his sword; he hath bent his bow, and made it ready.
Son of man, prophesy, and say, Thus saith the LORD; Say, A sword, a sword is sharpened, and also furbished: It is sharpened to make a sore slaughter; it is furbished that it may glitter: should we then make mirth? it contemneth the rod of my son, as every tree.
Make bright the arrows; gather the shields: the LORD hath raised up the spirit of the kings of the Medes: for his device is against Babylon, to destroy it; because it is the vengeance of the LORD, the vengeance of his temple.
And he hath given it to be furbished, that it may be handled: this sword is sharpened, and it is furbished, to give it into the hand of the slayer.
It is sharpened to make a sore slaughter; it is furbished that it may glitter: should we then make mirth? it contemneth the rod of my son, as every tree.
Who whet their tongue like a sword, and bend their bows to shoot their arrows, even bitter words:
They have sharpened their tongues like a serpent; adders' poison is under their lips. Selah.