Template:Apostles
Apostolos
The word Apostolos is from the Greek word apostello meaning to send, to order (one) to go to a place appointed. An ambassador from Greece would be called an Apostolos and certainly the Apostles were ambassadors from the kingdom of God to the world. It appears 78 times as apostle but twice as messenger. It could include anyone who is a delegate, messenger, one sent forth with orders. While it might be "specifically applied to the twelve apostles of Christ" but in a broader sense applied to others who are spiritually sent or delegated by God as prophets or teachers or any task.
The kingdom of God is a government of servants and there are no offices of authority of men over men. But men may delegate authority over things that by their nature and circumstance belong to God. This would be things freely given to men who belonged to God. The apostles seemed to actually belong to God as they considered themselves to be bondservants.