15 When the Philistines were at war again with Israel, David and his servants with him went down and fought against the Philistines; and David grew faint. 16 Then Ishbi-Benob, who was one of the sons of the giant, the weight of whose bronze spear was three hundred shekels, who was bearing a new sword, thought he could kill David. 17 But Abishai the son of Zeruiah came to his aid, and struck the Philistine and killed him. Then the men of David swore to him, saying, "You shall go out no more with us to battle, lest you quench the lamp of Israel."
Matthew Henry's Commentary on 2 Samuel 21:15-17
Commentary on 2 Samuel 21:15-22
(Read 2 Samuel 21:15-22)
These events seem to have taken place towards the end of David's reign. David fainted, but he did not flee, and God sent help in the time of need. In spiritual conflicts, even strong saints sometimes wax faint; then Satan attacks them furiously; but those who stand their ground and resist him, shall be relieved and made more than conquerors. Death is a Christian's last enemy, and a son of Anak; but through Him that triumphed for us, believers shall be more than conquerors at last, even over that enemy.