This expedition to Gibeon may have been for the purpose of shifting his metropolis to his own tribe of Benjamin, and to his family place, "Gibeah of Saul," close to Gibeon, with the further purpose of attacking the kingdom of David. "To go out" 2 Samuel 2:12-13 is a technical phrase for going out to war 1 Samuel 18:30.

And Abner the son of Ner,.... Who was before captain of Saul's host, and now of Ishbosheth's:

and the servants of Ishbosheth the son of Saul; who seem to be not only his domestic servants, that waited upon him, or his courtiers, but his whole army by what follows:

went out from Mahanaim to Gibeon; came from the city on the other side Jordan, where perhaps they had been two years past, concerting schemes to bring all Israel under the government of Ishbosheth; in which they had succeeded, only Judah stood out with David; and in order to reduce that tribe, they passed over Jordan and came to Gibeon, a city in Benjamin. See Joshua 18:25.

War between the supporters of Ishbosheth and those of David. - 2 Samuel 2:12, 2 Samuel 2:13. When Abner had brought all Israel under the dominion of Ishbosheth, he also sought to make Judah subject to him, and went with this intention from Mahanaim to Gibeon, the present Jib, in the western portion of the tribe of Benjamin, two good hours to the north of Jerusalem (see at Joshua 9:3), taking with him the servants, i.e., the fighting men, of Ishbosheth. There Joab, a son of Zeruiah, David's sister (1 Chronicles 2:16), advanced to meet him with the servants, i.e., the warriors of David; and the two armies met at the pool of Gibeon, i.e., probably one of the large reservoirs that are still to be found there (see Rob. Pal. ii. pp. 135-6; Tobler, Topogr. v. Jerusalem, ii. pp. 515-6), the one encamping upon the one side of the pool and the other upon the other.

And Abner the son of Ner, and the servants of Ishbosheth the son of Saul, went out from Mahanaim to Gibeon.

2:12 Went out - To fight with David's army, and to bring back the rest of the kingdom to Saul's house.

12. Abner . and the servants of Ish-bosheth . went out from Mahanaim to Gibeon-This town was near the confines of Judah, and as the force with which Abner encamped there seemed to have some aggressive design, David sent an army of observation, under the command of Joab, to watch his movements.

2:8-17. The nation in general refused David. By this the Lord trained up his servant for future honour and usefulness; and the tendency of true godliness was shown in his behaviour while passing through various difficulties. David was herein a type of Christ, whom Israel would not submit to, though anointed of the Father to be a Prince and a Saviour to them. Abner meant, Let the young men 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 thus trifle with human blood.