Albert Barnes Commentary 2 Samuel 16:3

"And the king said, And where is thy master`s son? And Ziba said unto the king, Behold, he abideth at Jerusalem; for he said, To-day will the house of Israel restore me the kingdom of my father." — 2 Samuel 16:3 (ASV)

Your master’s son - Meaning Saul’s grandson (2 Samuel 9:6). David asks the question, evidently hurt by the apparent ingratitude of Mephibosheth. It is impossible to say whether Mephibosheth was entirely guiltless or not. If Psalm 116 was composed by David after the quelling of Absalom’s rebellion, then Psalm 116:11 may contain David’s confession of his hasty judgment in this matter (2 Samuel 16:4).