John Gill Commentary 2 Samuel 2:12

"And Abner the son of Ner, and the servants of Ish-bosheth the son of Saul, went out from Mahanaim to Gibeon." — 2 Samuel 2:12 (ASV)

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) .