Jer 1:9-10, 9 Then the LORD put out his hand and touched my mouth. And the LORD said to me,“Behold, I have put my words in your mouth. 10…“
God by His angel touched the mouth and the lips of Isaiah to remove his iniquities (Isa 6). The same God would touch Jeremiah’s mouth and put His words in him.
The significance of the touching of the mouth may be seen with Jesus’ message to His disciples in Mark 13:10-11, “10 And the gospel must first be preached to all the nations 11 But when they arrest you and deliver you up, do not worry beforehand, or premeditate what you will speak. But whatever is given you in that hour, speak that; for it is not you who speak, but the Holy Spirit.”
Here as with Jeremiah, the disciples would speak, not as the principal authors but instruments. This knowledge ought to point us back to Him for assurance that our effectiveness is only by and through Him. Note how this plays out in vs 10, Jeremiah was to speak, prophesy, forth tell. Some of the prophesies would pluck or breakdown. Some would destroy and overthrow and some for good would build and plant. Again the effectiveness of his ministry would solely depend on God working in and through him, “for it is God who works in you, both to will and to work for his good pleasure.”, Eph 2:13.