If the axe is blunt, and one doesn't sharpen the edge, then he must use more strength; but skill brings success.
1 Samuel 13:20
but all the Israelites went down to the Philistines, to sharpen every man his plowshare, mattock, axe, and sickle;
Iron sharpens iron; so a man sharpens his friend's countenance.
if I whet my glittering sword, My hand take hold on judgment; I will render vengeance to my adversaries, and will recompense those who hate me.
If a man doesn't relent, he will sharpen his sword; he has bent and strung his bow.
Son of man, prophesy, and say, Thus says Yahweh: Say, A sword, a sword, it is sharpened, and also furbished; it is sharpened that it may make a slaughter; it is furbished that it may be as lightning: shall we then make mirth? the rod of my son, it condemns every tree.
Make sharp the arrows; hold firm the shields: Yahweh has stirred up the spirit of the kings of the Medes; because his purpose is against Babylon, to destroy it: for it is the vengeance of Yahweh, the vengeance of his temple.
It is given to be furbished, that it may be handled: the sword, it is sharpened, yes, it is furbished, to give it into the hand of the killer.
it is sharpened that it may make a slaughter; it is furbished that it may be as lightning: shall we then make mirth? the rod of my son, it condemns every tree.
who sharpen their tongue like a sword, and aim their arrows, deadly words,
They have sharpened their tongues like a serpent. Viper's poison is under their lips. Selah.