David's response to adversary's death

Joab was still sore at Abner over his brother's death, he wanted revenge, and he got it. David however didn't like what happened, in fact he rebuked Joab for what he had done. He made Joab even go to the funeral for the man he had killed. In his respect to Abner, David decided to fast. His fasting showed he didn't sanction Abner's death. Has your adversary hurt you? How are you responding?