Charles Ellicott Commentary 1 Chronicles 12:20

"As he went to Ziklag, there fell to him of Manasseh, Adnah, and Jozabad, and Jediael, and Michael, and Jozabad, and Elihu, and Zillethai, captains of thousands that were of Manasseh." — 1 Chronicles 12:20 (ASV)

As he went to Ziklag. — On his dismissal by the Philistine princes, David returned with his men to Ziklag (1 Samuel 30:1). On the way he was joined by the Manassite chieftains, probably before the battle which decided the fate of Saul and his sons (1 Samuel 29:11).

Jozabad. — The repetition may be a scribe’s error. (Compare to 1 Chronicles 12:10; 1 Chronicles 12:13, where we find the name Jeremiah given twice over.)

Captains of the thousands that were of Manasseh. — (and 1 Chronicles 13:1; 1 Chronicles 15:25; 1 Chronicles 26:26.) The term “thousand” interchanges with “father-house” (clan); and perhaps each clan originally furnished 1,000 warriors to the tribal host.