'Sharp' in the Bible

The sin of Judah is recorded with a pen of iron, and with the sharp point of a jewel it is cut on their hearts of stone, and on the horns of their altars for a sign to them:

Make the horses ready, and get up, you horsemen, and take your places with your head-dresses; make the spears sharp and put on the breastplates.

Make sharp the arrows; hold firm the shields: Jehovah hath 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 Jehovah, the vengeance of his temple.