Adam Clarke on 2 Samuel 19:32

Barzillai was a very aged man - This venerable person had given full proof of his attachment to David by the supplies he had given him when he lay at Mahanaim, where his case was all but desperate; the sincerity of his congratulations now none can suspect. David's offer to him was at once noble and liberal: he wished to compensate such a man, and he wished to have at hand such a friend.