a man of God = the man (Hebrew. 'ish, App-14.) of God (Hebrew. Elohim.App-4.): i.e. a prophet. See App-49.
Maaseiah, &c. He was the deputy of the High Priest. Compare Jer_52:24. 2Ki_25:18. Probably the same whose son Zephaniah, after the carrying away of Maaseiah with Jehoiachin (Jer_29:1), held office under Zedekiah (Jer_21:1; Jer_29:5; Jer_37:3).
keeper of the door = keeper of the threshold. There were three. See 2Ki_25:18. 2Ch_31:14.