IONADAB (Hebr. Yehoïnâdâb, or Yônâdâb). — Name of two figures in the Old Testament.
1. Son of Semmaa, brother of David. Shrewd and perceptive, he was the evil genius of his cousin Amnon, to whom he suggested how to satisfy his brutal passion for Thamar. When the false news of the slaughter of his sons reached David, I. correctly assured him that Absalom’s vengeance had fallen only upon Amnon (II Sam. 13).
2. Son of Rechab, a faithful Yahwist whom Jehu wished to have with him when he set out to destroy the house of Ahab and idolatry (II Reg. 10, 15 ff. 23). I. sought to preserve his descendants from the harmful influence of Canaanite civilization and prescribed that they remain semi-nomadic (Jer. 35).
Bibl.: L. Desnoyers, Histoire du peuple hébreu, II, Paris 1930, pp. 279–82; A. Condamin, Le livre de Jérémie, 3e éd., Francesca Spadafora 1936, pp. 256 ff.