2 Samuel 3:1 (BSB)

Now the war between the house of Saul and the house of David was protracted. And David grew stronger and stronger, while the house of Saul grew weaker and weaker.

From 2 Samuel 3. Also in the ESV.

Commentary on 2 Samuel 3:1

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on 2 Samuel 3:1-6: Here is, I. The struggle that David had with the house of Saul before his settlement in the throne was completed, Sa2 3:1. 1. Both sides contested. Saul's house, though beheaded and diminished, would not fall tamely. It is not strange between them, but one would wonder it should be a long war, when David's house had right on its side, and therefore God on...
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on 2 Samuel 3:1: Now there was a long war between the house of Saul and the house of David,.... The recent battle, though so much in favour of David, did not, put an end to the war between him and Ishbosheth, which lasted five years longer; for it was when Ishbosheth had reigned two years that that battle was fought, and he reigned five years longer; for not...
• Geneva Bible Notes (Reformed), Geneva Bible Study Notes on 2 Samuel 3:1: Now there was long war between the house of Saul and the house of David: but David waxed stronger and stronger, and the house of Saul waxed weaker and weaker. (a) That is, without intermission enduring two years, which was the whole reign of Ishbosheth.
• Adam Clarke (Methodist), Clarke's Commentary on the Bible on 2 Samuel 3:1: There was long war - Frequent battles and skirmishes took place between the followers of David and the followers of Ish-bosheth, after the two years mentioned above, to the end of the fifth year, in which Ish-bosheth was slain by Rechab and Baanah.