Joab is angry that David made peace with Abner
Joab was angry with David for making peace with Abner.
Key passages
2 Sa 3:22–25

And look, the servants of David and Joab came from the raid, and they brought much plunder with them. But Abner was not with David at Hebron, for he had dismissed him, and he had gone in peace. When Joab and all the army that was with him came, they told Joab, “Abner the son of Ner came to …

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