Jeremiah 29:26
The Lord hath made thee priest in the stead of Jehoiada the priest, that ye should be officers in the house of the Lord, for every man that is mad, and maketh himself a prophet, that thou shouldest put him in prison, and in the stocks.
Cross-reference
Jeremiah 29:27 continues the same letter, asking why Jeremiah hasn't been stopped — the immediate context of the false prophet accusation.
Jeremiah 38:6 shows the same authority from Jeremiah 29:26 being used against Jeremiah himself, a true prophet. Ironic contrast.
Hosea 9:7 directly calls false prophets 'mad' and 'fools', mirroring the accusation in Jeremiah — a strong thematic parallel.
2 Kings 9:11 uses 'mad fellow' for a true prophet, showing the term was commonly applied to prophets, both false and true.
2 Chronicles 16:10 records King Asa imprisoning prophet Hanani, a parallel to the priest's authority to imprison prophets in Jeremiah 29:26.
2 Chronicles 18:26 has King Ahab imprison Micaiah the prophet, similar to the prison authority in Jeremiah 29:26.
2 Kings 11:15 shows Jehoiada the priest acting boldly, the same Jehoiada whose position Shemaiah's letter references.
2 Kings 11:18 describes Jehoiada's role in temple reform, providing background for the priestly office mentioned in the letter.
Mark 3:21 records Jesus' family saying He is 'beside himself' — the same accusation of madness levelled at prophets, here against the Son of God.
John 10:20 has the crowd saying Jesus 'hath a devil and is mad' — again the madness accusation directed at a true prophet.