Jeremiah 1:9,10 - Joseph Benson’s Commentary on the Old and New Testaments

Then the Lord put forth his hand, and touched my mouth This appeared to the prophet to be done in his vision; whereby he was taught that the divine help should go along with him, that the gift of utterance should be bestowed upon him, and that he should be able to declare the divine commands in a proper spirit and manner: compare Isaiah 6:7; and Isaiah 51:16. Behold, I have put my words in thy mouth By the seeing of this symbolical action in his vision, and the hearing of these words, Jeremiah could not but be assured that he should be able to speak in the proper language of a prophet, or with words becoming his office, and that he should have that firmness and boldness given him which were necessary for the purpose. Jeremiah does not indeed equal Isaiah in eloquence of speech, but he seems to have been no way inferior to him in firmness of mind. See, I have this day set thee over the nations Namely, to speak to them in my name, for this is all that is meant here by being set over them. To root out and to pull down, &c. In the style of Scripture the prophets are said to do what they declare shall be done; and therefore Jeremiah is here said to root out, &c., because he was authorized to make known the purposes of God, and because the events here mentioned would follow in consequence of his prophecies. See Isaiah 6:9; and Bishop Newton on the Prophecies, vol. 1.