Barzillai was quite old, eighty years of age, and since he was a very wealthy man, he had provided for the king while he stayed in Mahanaim.
David had already graced the triumphs of his restoration with the generous remission of the injuries that had been done to him; we have him here gracing them with a no less generous reward of the kindnesses that had been shown to him.
Commenting on 2 Samuel 19:31-39
Now Barzillai was a very aged man, even fourscore years old,.... Which was ten years beyond the common term of man's life, and reckoned a very great age in David's time, and has been ever since, and still is, see Psa 90:10, and he had provided the king of sustenance while he lay at Mahanaim: had supported him and his family, furnished him with provisions...
THE ISRAELITES BRING THE KING BACK. (2Sa. 19:9-43) all the people were at strife throughout all the tribes of Israel--The kingdom was completely disorganized. The sentiments of three different parties are represented in Sa2 19:9-10 : the royalists, the adherents of Absalom who had been very numerous, and those who were indifferent to the Davidic dynasty.
Commenting on 2 Samuel 19:9-43