John Gill Commentary Jeremiah 23:37

"Thus shalt thou say to the prophet, What hath Jehovah answered thee? and, What hath Jehovah spoken?" — Jeremiah 23:37 (ASV)

Thus shall you say to the prophet
To Jeremiah, or any true prophet of the Lord; after the following manner should everyone address him, that made any inquiry of the will of the Lord by him: what has the Lord answered you? and what has the Lord spoken ?
this is repeated from (Jeremiah 23:35) ; for the confirmation of it, and for the direction of the people, and to show how much the Lord approved of such a way of behaving towards his prophet, and himself by him.