Adam Clarke on Jeremiah 1:6

I cannot speak - Being very young, and wholly inexperienced, I am utterly incapable of conceiving aright, or of clothing these Divine subjects in suitable language. Those who are really called of God to the sacred ministry are such as have been brought to a deep acquaintance with themselves, feel their own ignorance, and know their own weakness. They know also the awful responsibility that attaches to the work; and nothing but the authority of God can induce such to undertake it. They whom God never called run, because of worldly honor and emolument: the others hear the call with fear and trembling, and can go only in the strength of Jehovah. "How ready is the man to go,

Whom God hath never sent!

How timorous, diffident, and slow,

God's chosen instrument!"