That thou quench not the light of Israel - David is here considered as the lamp by which all Israel was guided, and without whom all the nation must be involved in darkness. The lamp is the emblem of direction and support. Light is used in this sense by Homer: -

Ουδε τι Πατροκλῳ γενομην φαος, αυδ' ἑταροισι

Τοις αλλοις, οἱ δη πολεες δαμεν Ἑκτορι διῳ.

Iliad, lib. xviii. ver. 102.

"I have neither been a Light to Patroclus nor to his companions, who have been slain by the noble Hector."

But Abishai the son of Zeruiah succoured him,.... Observing him in danger, made haste to his relief:

and smote the Philistine, and killed him; it seems as if Abishai engaged with the Philistine, and killed him; but inasmuch as it will bear to be interpreted of David, and since the four giants here and hereafter mentioned are said to fall by the hand of David and his servants, 2 Samuel 21:22, it may be thought that this man fell by his hand; seeing it is clear that all the rest fell by the hands of his servants:

then the men of David sware unto him; after they had observed the danger he was exposed unto, and how narrowly he escaped with his life:

saying, thou shalt go no more with us to battle; they had persuaded him not to go to the battle with Absalom; they had suffered him to go with them now, he being, no doubt, forward and pressing to it; but now they were resolute, and determined he should never go more:

that thou quench not the light of Israel; signifying that their glory and prosperity depended on his life, and that, should he be taken away, they should be in affliction and adversity, their honour and their happiness would be at an end; the Targum is,"thou mayest not extinguish the kingdom of Israel,''the light and glory of it.

The danger into which the king had been brought in this war, and out of which he had been rescued solely by Abishai's timely help, induced his attendants to make him swear that he would not go into battle any more in person. לו נשׁבּע, administered an oath to him, i.e., fixed him by a promise on oath. תכבּה ולא תכבּ, "and shalt not extinguish the light of Israel." David had become the light of Israel from the fact that Jehovah was his light (2 Samuel 22:29), or, according to the parallel passage in Psalm 18:29, that Jehovah had lighted his lamp and enlightened his darkness, i.e., had lifted him out of a state of humiliation and obscurity into one of honour and glory. The light (or lamp) is a figure used to represent the light of life as continually burning, i.e., life in prosperity and honour. David's regal life and actions were the light which the grace of God had kindled for the benefit of Israel. This light he was not to extinguish, namely by going into the midst of war and so exposing his valuable life to danger.

But Abishai the son of Zeruiah succoured him, and smote the Philistine, and killed him. Then the men of David sware unto him, saying, Thou shalt go no more out with us to battle, that thou quench not the {n} light of Israel.

(n) For the glory and wealth of the country stands in the preservation of the godly magistrate.

light: Heb. candle, or, lamp

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.