The Lord delivered Paul from the people and from the Gentiles, associating him with Christ in glory. He sent him forth into the world which is without God, as dark as pitch, to carry this testimony – to deliver them. What he was an eye witness of, was what he preached.
That same world is where you are sent. You are not apostles, but each one is to be a witness in his own little sphere. If you call yourselves Christians, you are set in the world to be the epistle of Christ before men.
What I see is that the vessels of testimony are those who are closest to the Lord. Mary Magdalene was not an Apostle, but she was able to tell the disciples of that which was their highest privilege; for her heart clung to Christ, and she found the world an empty sepulcher. If you want true knowledge, you must be near Christ in affection.