John Gill Commentary Jeremiah 1:7

"But Jehovah said unto me, Say not, I am a child; for to whomsoever I shall send thee thou shalt go, and whatsoever I shall command thee thou shalt speak." — Jeremiah 1:7 (ASV)

But the Lord said to me, say not, I am a child This excuse will not be admitted: for you will go to all that I will send you ; either to "every place", as the Targum paraphrases; or "to all persons to whom" he should be sent, as the Septuagint and Arabic versions render the words; or "to all things for which" he should send him, as the Syriac and Vulgate Latin versions. The sense is, that he should go everywhere, and to every person, and on every errand and message he should be sent to and with: and whatever I command you, you will speak ; out and openly, and keep back nothing through the fear of men; as follows: