2 Samuel 2:15

A long civil war followed between Judah, led by David, and the northern tribes, led by Saul’s family. These events led directly to the murder of Abner (2 Samuel 3:22–39).

After Saul died, those loyal to David (the tribe of Judah) came into conflict with those loyal to Saul’s son Ish-bosheth (the remaining tribes of Israel).

At this time, the Philistines controlled much of the land west of the Jordan River. They likely encouraged this division among the Israelites because a divided people were easier for them to control.

Abner said to Joab, Let the young men now arise, and play before us--Some think that the proposal was only for an exhibition of a little tilting match for diversion. Others suppose that, both parties being reluctant to commence a civil war, Abner proposed to leave the contest to the decision of twelve picked men on either side. This fight by championship instead of terminating the matter, inflamed the fiercest passions of the two rival parties; a general engagement ensued, in which Abner and his forces were defeated and put to flight.

Here is, I. A rivalship between two kings - David, whom God made king, and Ishbosheth, whom Abner made king. One would have thought, when Saul was slain, and all his sons that had sense and spirit enough to take the field with him, David would come to the throne without any opposition, since all Israel knew, not only how he had signalized himself, but how manifestly God had designated him to it; but such a spirit of contradiction is there, in the devices of men, to the counsels of God, that such a weak and silly thing as Ishbosheth, who was not thought fit to go with his father to the battle, shall yet be thought fit to succeed him in the government, rather than David shall come peaceably to it. Herein David's kingdom was typical of the Messiah's, against which the heathens rage and the rulers take counsel, Psa 2:1, Psa 2:2. 1. Abner was the person who set up Ishbosheth in competition with David, perhaps in his zeal for the lineal succession (since they must have a king like the nations, in this they must be like them, that the crown must descend from father to son), or rather in his affection to his own family and relations (for he was Saul's uncle), and because he had no other way to secure to himself the post of honour he was in, as captain of the host. See how much mischief the pride and ambition of one man may be the occasion of. Ishbosheth would never have set up himself if Abner had not set him up, and made a tool of him to serve his own purposes. 2. Mahanaim, the place where he first made his claim, was on the other side Jordan, where it was thought David had the least interest, and being at a distance from his forces they might have time to strengthen themselves. But having set up his standard there, the unthinking people of all the tribes of Israel (that is, the generality of them) submitted to him (Sa2 2:9), and Judah only was entirely for David. This was a further trial of the faith of David in the promise of God, and of his patience, whether he could wait God's time for the performance of that promise. 3. Some difficulty there is about the time of the continuance of this competition. David reigned about seven years over Judah only (Sa2 2:11), and yet (Sa2 2:10) Ishbosheth reigned over Israel but two years: before those two years, or after, or both, it was in general for the house of Saul (Sa2 3:6), and not any particular person of that house, that Abner declared. Or these two years he reigned before the war broke out (Sa2 2:12), which continued long, even the remaining five years, Sa2 3:1.
II. An encounter between their two armies.
1. It does not appear that either side brought their whole force into the field, for the slaughter was but small, Sa2 2:30, Sa2 2:31. We may wonder, (1.) That the men of Judah did not appear and act more vigorously for David, to reduce all the nation into obedience to him; but, it is likely, David would not suffer them to act offensively, choosing rather to wait till the thing would do itself or rather till God would do it for him, without the effusion of Israelitish blood; for to him, as a type of Christ, that was very precious, Psa 72:14. Even those that were his adversaries he looked upon as his subjects, and would treat them accordingly. (2.) That the men of Israel could in a manner stand neuter, and sit down tamely under Ishbosheth, for so many years, especially considering what characters many of the tribes displayed at this time (as we find, Ch1 12:23, etc.): Wise men, mighty men, men of valour, expert in war, and not of double heart, and yet for seven years together, for aught that appears, most of them seemed indifferent in whose hand the public administration was. Divine Providence serves its own purposes by the stupidity of men at some times and the activity of the same persons at other times; they are unlike themselves, and yet the motions of Providence are uniform.
2. In this battle Abner was the aggressor. David sat still to see how the matter would fall, but the house of Saul, and Abner at the head of it, gave the challenge, and they went by the worst. Therefore go not forth hastily to strive, nor be forward to begin quarrels, lest thou know not what to do in the end thereof, Pro 25:8. A fool's lips and hands enter into contention.
3. The seat of the war was Gibeon. Abner chose it because it was in the lot of Benjamin, where Saul had the most friends; yet, since he offered battle, Joab, David's general, would not decline it, but there joined issue with him, and met him by the pool of Gibeon, Sa2 2:13. David's cause, being built upon God's promise, feared not the disadvantages of the ground. The pool between them gave both sides time to deliberate.
4. The engagement was at first proposed by Abner, and accepted by Joab, to be between twelve and twelve of a side. (1.) It should seem this trial of skill began in sport. Abner made the motion (Sa2 2:14): Let the young men arise and play before us, as gladiators. Perhaps Saul had used his men to these barbarous pastimes, like a tyrant indeed, and Abner had learnt of him to make a jest of wounds and death and divert himself with the scenes of blood and horror. He meant, "Let them fight before us," when he said, "Let them play before us." Fools thus make a mock at sin. but he is unworthy the name of a man that can be thus prodigal of human blood, that can thus throw about firebrands, arrows, and death, and say, Am not I in sport? Pro 26:18, Pro 26:19. Joab, having been bred up under David, had so much wisdom as not to make such a proposal, yet had not resolution enough to resist and gainsay it when another made it; for he stood upon a point of honour, and thought it a blemish to his reputation to refuse a challenge, and therefore said, Let them arise; not that he was fond of the sport, or expected that the duels would be decisive, but he would not be hectored by his antagonist. How many precious lives have thus been sacrificed to the caprices of proud men! Twelve of each side were accordingly called out as champions to enter the lists, a double jury of life and death, not of others', but their own; and the champions on Abner's side seem to have been most forward, for they took the field first (Sa2 2:15), having perhaps been bred up in a foolish ambition thus to serve the humour of their commander-in-chief. But, (2.) However it began, it ended in blood (Sa2 2:16): They thrust every man his sword into his fellow's side (spurred on by honour, not by enmity); so they fell down together, that is, all the twenty-four were slain, such an equal match were they for one another, and so resolute, that neither side would either beg or give quarter; they did as it were by agreement (says Josephus) dispatch one another with mutual wounds. Those that strike at other men's lives often throw away their own and death only conquers and rides in triumph. The wonderful obstinacy of both sides was remembered in the name given to the place: Heldath-hazzurim - the field of rocky men, men that were not only strong in body, but of firm and unshaken constancy, that stirred not at the sight of death. Yet the stout-hearted were spoiled, and slept their sleep, Psa 76:5. Poor honour for men to purchase at so vast an expense! Those that lose their lives for Christ shall find them.
5. The whole army at length engaged, and Abner's forces were routed, Sa2 2:17. The former was a drawn battle, in which all were killed on both sides, and therefore they must put it upon another trial, in which (as it often happens) those that gave the challenge went away with loss. David had God on his side; his side therefore was victorious.

Let the young men - play before us - This was diabolical play, where each man thrust his sword into the body of the other, so that the twenty-four (twelve on each side) fell down dead together! But this was the signal for that sanguinary skirmish which immediately took place.

Then there arose and went over by number twelve of Benjamin,.... Whom Abner had picked out of that tribe, being his own, and whom he knew to be stout and courageous men, and closely attached to him. It seems by this as if Abner's men:

which pertained to Ishbosheth, the son of Saul, passed over the pool of Gibeon unto Joab's men; so forward were they to engage in this duel, and it makes it still more appear that they were the aggressors:

and twelve of the servants of David; of his army under Joab, whom Joab either selected, or they, offered themselves as willing to engage with the twelve that were come over.

Abner selected all his combatants out of Benjamin, both because that was a warlike and valiant tribe, and that he might give the more honour to his own tribe.

Abner then proposed to Joab that the contest should be decided by a single combat, probably for the purpose of avoiding an actual civil war. "Let the young men arise and wrestle before us." שׂחק, to joke or play, is used here to denote the war-play of single combat. As Joab accepted this proposal, twelve young warriors for Benjamin and Ishbosheth, and twelve from David's men, went over, i.e., went out of the two camps to the appointed scene of conflict; "and one seized the other's head, and his sword was (immediately) in the side of the other (his antagonist), so that they fell together." The clause רעהוּ בּצד וחרבּו is a circumstantial clause: and his sword (every one's sword) was in the side of the other, i.e., thrust into it. Sending the sword into the opponent's side is thus described as simultaneous with the seizure of his head. The ancient translators expressed the meaning by supplying a verb (ἐνέπηξαν, defixit: lxx, Vulg.). This was a sign that the young men on both sides fought with great ferocity, and also with great courage. The place itself received the name of Helkath-hazzurim, "field of the sharp edges," in consequence (for this use of zur, see Psa 89:44).