They buried Avner at Hevron; the king wept aloud at Avner’s grave, and all the people wept.
There is an interesting dimension to a King of Israel that seems to be overlooked: he is to be the exemplary Jew. He is meant to walk out Torah to the fullest extent, that is one of his core functions. The people should be able to look to him and act how he acts. As David is cementing his rule over a united Israel, he mourns for an enemy-turned ally. The enemy status of Avner is difficult to deal with here because they are both sons of Ya’akov, but there was violence between brothers as Sha’ul reign had ended and those around him tried to pass the crown to his son Ish-boshet.
Walking In Liberty 