'Rod' in the Bible

I will be his father, and he shall be my son. If he commit iniquity, I will chasten him with the rod of men, and with the stripes of the children of men:

And again there was war with the Philistines at Gob, and Elhanan, the son of Jair the Beth-lehemite, put to death Goliath the Gittite, the stem of whose spear was like a cloth-worker's rod.

But anyone touching them has to be armed with iron and the rod of a spear; and they will be burned with fire, every one of them.

And he hath smitten the Egyptian man, a man of appearance, and in the hand of the Egyptian is a spear, and he goeth down unto him with a rod, and taketh violently away the spear out of the hand of the Egyptian, and slayeth him with his own spear.