Charles Ellicott Commentary Jeremiah 29:26

"Jehovah hath made thee priest in the stead of Jehoiada the priest, that there may be officers in the house of Jehovah, for every man that is mad, and maketh himself a prophet, that thou shouldest put him in the stocks and in shackles." — Jeremiah 29:26 (ASV)

The Lord has made you priest in the stead of Jehoiada ... —The priest so named had apparently been deposed, as not favoring the stringent policy of the party of revolt. As Sagan, it was probably his special duty to maintain order in the Temple, and punish pretenders to the gift of prophecy, and the letter reproaches him for his lukewarm timidity in discharging that duty. In the word “mad,” as in 2 Kings 9:11, Hosea 9:7, we have the habitual term of scorn applied to such pretenders. On the punishment of the stocks, see Note on Jeremiah 20:2. The word translated “prison” is probably another form of punishment like that of the stocks.