Albert Barnes Commentary 1 Kings 1:42

"While he yet spake, behold, Jonathan the son of Abiathar the priest came: and Adonijah said, Come in; for thou art a worthy man, and bringest good tidings." — 1 Kings 1:42 (ASV)

Jonathan had acted in a similar capacity, as a carrier of intelligence, in the time of Absalom’s attempt (2 Samuel 15:36; 2 Samuel 17:17), but at that time, like his father, he was faithful to David and was “a valiant man,” “a virtuous man,” or “a man of worth” (see 1 Kings 1:52; Proverbs 12:4).