And Ishbi-benob, one of the descendants of the giants, whose spear weighed three hundred shekels of bronze, and who was armed with a new sword, thought to kill David. - 2 Samuel 21:16
Late in King David's reign, there was a series of wars in which David and his servants fell four descended from the giants in Gath. In the first, Ishbi-benob thought to kill David when he grew weary, but Abishai the son of Zeruiah killed the Philistine. That was the last time David's men allowed him to go out with them to battle, lest he quench the lamp of Israel. (2 Samuel 21:15-22)
Ishbi-benob was a descendent of the giants, and his spear weighed 300 shekels of bronze. (2 Samuel 21:16)