Albert Barnes Commentary 2 Samuel 9:4

"And the king said unto him, Where is he? And Ziba said unto the king, Behold, he is in the house of Machir the son of Ammiel, in Lo-debar." — 2 Samuel 9:4 (ASV)

David reaped the fruit of his kindness to Mephibosheth, for when he fled from Absalom, Machir, son of Ammiel, was one of those who generously provided for him and his army. According to 1 Chronicles 3:5, Ammiel (whose name is given in reverse as Eliam in 2 Samuel 11:3) was the father of Bath-sheba. If this is the same Ammiel, then Machir would be Bath-sheba’s brother. However, the name is fairly common (Numbers 13:12; 1 Chronicles 26:5, and other passages).

Lo-debar was evidently east of the Jordan River and near Ish-bosheth’s capital, Mahanaim (2 Samuel 17:27), but it has not been identified by any modern traveler. Some think it is likely the same place as Debir (Joshua 13:26).