Matthew Poole and continuators on 2 Samuel 9:1

AND David said , Is there yet any that is left of the house of Saul , that I may shew him kindness for Jonathans sake?

David's Wars being ended, he set himself to the Administration of Justice to all his People, chap. 8. 15. And amongst others he minds his just debt and obligation to Ionathan and his Family.

He saith not of the house of Ionathan, for he knew not of any Son which he had left, and therefore thought his kindness and obligation was to pass to the next of his Kindred. As for Mephibosheth, he was very young and obscure, and possibly concealed by his Friends, lest David should cut him off from jealousie of State, as hath been usual among Princes in like case, and therefore was unknown to David, as well he might be, especially when David's head and hands were full of War with divers and Potent Enemies, as they had hitherto been.