What does Jeremiah 29:25 mean?

This is what the Lord of all, the God of Israel, says: You sent letters in your own name to all the people in Jerusalem, to Zephaniah son of Maaseiah the priest, and to all the other priests. Jeremiah 29:25 - Modern Text Bible

(Shemaiah has been spreading his own messages, pretending they’re from God, and sending them to the religious leaders in Jerusalem.)