15 Once again the Philistines were at war with Israel. And when David and his men were in the thick of battle, David became weak and exhausted. 16 Ishbi-benob was a descendant of the giants ; his bronze spearhead weighed more than seven pounds, and he was armed with a new sword. He had cornered David and was about to kill him. 17 But Abishai son of Zeruiah came to David's rescue and killed the Philistine. Then David's men declared, "You are not going out to battle with us again! Why risk snuffing out the light 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.