2 Samuel 2:10

Ishbosheth Saul's son was forty years old when he began to reign over Israel, and reigned two years. But the house of Judah followed David.

Ish-bosheth ... reigned two years. It was not until seven years and a half after Saul's death that the way was paved for David's elevation to the throne of Israel (2 Samuel 2:11). So that if Ish-bosheth had succeeded immediately on the death of his father, his reign in Israel must have been commensurate with that of David in Hebron. The statement, therefore, that 'Ish-bosheth reigned two years' must refer either to the time that elapsed after he was made king, before the war broke out between him and David, or to an inter-regnum of 5 1/2 five years and six months in Israel, when, through the great influence of Abner, he was raised to the throne of his father, and had occupied it for two years when he was cut off.