‘Be not afraid of their faces.’ The Hebrew is more, ‘Be not afraid in their presence’, and our translators have gone for faces and it's very effective.
It is the same with us. If we speak God's word, there will be suffering in some shape or form: resentment, scorn, contempt, rejection. But it will never be allowed to crush us. We may, like apostle Paul, go to prison. There may be physical persecution, but God will see us through and his word will stand at the end, and our work will stand when all our assailants have fallen.
‘Be not afraid of their faces: for I am with thee.’ How do you avoid fear? How do you avoid the discomfort, and the crushing sensation of being scorned and ridiculed and rejected, set at nought? You keep your mind on this: ‘I am with thee’, and that is everything. That is so powerful; that is such a comfort and such a strength. There is an implicit warning here, ‘for I am with thee.’ Be not afraid of stony faces, hostile faces, indifferent faces, contemptuous faces.
What is more, his word survived the ordeal and the word went out. Of course we have it here now. We have all the chapters of Jeremiah. We have his lamentations also. We have such a large portion of the word of God through his ministry. The promise of preservation applied to him, and to his work. Not everybody is promised preservation: there are martyrs for the cause, but even they do not know death in spiritual terms.