Albert Barnes Commentary Jeremiah 36:11

"And when Micaiah the son of Gemariah, the son of Shaphan, had heard out of the book all the words of Jehovah," — Jeremiah 36:11 (ASV)

Probably as his father had lent Jeremiah the hall, Michaiah had been commanded to bring Gemariah (Jeremiah 36:12) news, as soon as the reading was over, of the nature of the prophet’s words and the effect produced by them on the people.