Luke 24:48

Ye are witnesses of these things - He gave them a full commission to proclaim these glad tidings of peace and salvation to a lost world. The disciples were witnesses not only that Christ had suffered and rose again from the dead; but also that he opens the understanding by the inspiration of his Spirit, that he gives repentance, that he pardons sin, and purifies from all unrighteousness, and that he is not willing that any should perish, but that all should come unto the knowledge of the truth and be saved. And these are the things of which their successors in the Gospel ministry must bear witness. As far as a man steadily and affectionately proclaims these doctrines, so far God will bless his labor to the salvation of those who hear him. But no man can with any propriety bear witness of that grace that saves the soul, whose own soul is not saved by that grace.