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.
Cross-reference
2 Samuel 2:17 describes the very battle that sparked the long war between David and Saul's house, showing the conflict's origin.
2 Samuel 2:31 records a battle where David's men killed 360 of Saul's side, illustrating the ongoing war where David grew stronger.
2 Samuel 5:10 directly states David became greater and greater because God was with him, echoing the growth described in 3:1.
2 Samuel 22:44 thanks God for delivering David from strife with his people, which refers to the war with Saul's house summarized in 3:1.
1 Chronicles 11:9 repeats that David grew more powerful because the Lord was with him, paralleling 3:1's description of his increasing strength.
1 Chronicles 12:22 explains why David grew stronger: men came daily to help him, forming a great army.
Psalm 89:23 echoes God's promise to beat down David's foes, which is fulfilled as Saul's house weakens and David grows stronger.
In 1 Kings 15:32, the identical phrase 'there was war between Asa and Baasha' parallels the chronic warfare here.
In 1 Kings 14:30, this same pattern of ongoing war between rival houses continues for Rehoboam and Jeroboam.
In 1 Kings 15:16, this same ongoing warfare pattern recurs between Asa and Baasha, mirroring the earlier house conflicts.