Notes on the Bible, by Albert Barnes, , at sacred-texts.com
2 Kings (2 Samuel) 9:4
David reaped the fruit of his kindness to Mephibosheth, for, when he fled from Absalom, Machir, the son of Ammiel, was one of those who were most liberal in providing him and his army with necessaries (marginal reference). According to Ch1 3:5, Ammiel (called inversely Eliam, Sa2 11:3) was the father of Bath-sheba. If this be the same Ammiel, Machir would be Bath-sheba's brother. However, the name is not a very uncommon one (Num 13:12; Ch1 26:5, etc.).
Lo-debar - Evidently on the east of Jordan River, and in the neighborhood of Ish-bosheth's capital, Mahanaim Sa2 17:27, but not identified by any modern traveler. Thought by some, not improbably, to be the same as Debir Jos 13:26.
2 Kings (2 Samuel) 9:6
Mephibosheth - Also called Merib-baal (and Meri-baal, probably by a clerical error, Ch1 9:40). The two names seem to have the same meaning: Bosheth, shame, being the equivalent for Baal, and Mephi (scattering or destroying, being equivalent to Merib (contending with). Compare Ish-bosheth and Esh-baal, Jerub-baal and Jerub-besheth.
He fell on his face - In fear. Such generosity to a fallen rival as David showed in restoring him his paternal property seemed to him scarcely credible.
2 Kings (2 Samuel) 9:8
Mephibosheth's humility of expression, even in the mouth of an Oriental, is painful. It was perhaps in part the result of his helpless lameness, and of the other misfortunes of his life.
A dead dog - The wild dogs of the East, which still abound in every town, are the natural objects of contempt and dislike.
2 Kings (2 Samuel) 9:9
Saul's servant - Josephus calls him one of Saul's freedmen. The difference this would make in Ziba's position would only be that instead of paying in the fruits of the confiscated land to David, he would have to pay them to Mephiboseth.
2 Kings (2 Samuel) 9:10
Fifteen sons ... - See Sa2 19:17, marginal reference.
2 Kings (2 Samuel) 9:11
Said the king - There is nothing in the Hebrew to warrant the insertion of these words. The words are: "So Mephibosheth ate at my table as one of the king's sons." Only it follows that the narrator is David himself.
2 Kings (2 Samuel) 9:12
Mephibosheth was five years old at Saul's death. He may have been thirteen at David's accession to the throne of Israel. In the eighth year of David's reign over all Israel he would have been twenty-one. His having a son at this time indicates that we are about the 10th year of David's reign.
Micha - Or Micah; who, as far as we know, was Mephibosheth's only son, and had a numerous posterity (marginal references).