2 Samuel 3:17

And Abner had communication with the elders of Israel, saying, Ye sought for David in times past to be king over you:

Abner treacherously deserted Ishbosheth in order to bring all the tribes of Israel over to David and to overthrow the throne that malice and ambition had established. He turned against Ishbosheth after becoming incensed with him, for Ishbosheth was weak and incompetent. Abner then offered to win Israel for David, David accepted his proposals, and dismissed him with honor to accomplish his purpose with the elders of Israel.