The Greek word "apostolos" corresponds to the Hebrew "shaliach," which means "messenger. The Greek word "apostolos" corresponds to the Hebrew "shaliach" and means "messenger. In the Septuagint it is used in its literal meaning "messenger" (3 Samuel 14:6), "ambassador" (Isaiah 18:2).

The word "apostle" also means "ambassadors in authority of him who sent them," "one who is sent with special authority," "disciple," "first follower," "special," "steadfast adherent," or "teacher of the true faith.

"Apostle" is a person who, by true knowledge of the Word of God, has been prompted to preach the good news of the necessity of establishing the kingdom of God's Will in man and society, of "resurrection," of reviving in the nations the true understanding and fulfillment of the Doctrine of Jesus Christ.

Every Apostle is a disciple of Jesus Christ, but not every disciple is an Apostle. Apostles are missionaries, preachers of early Christianity. 

In a narrower sense, the word Apostle (as already considered in the early "Church" of Christ) is a witness to the physical life of Christ and His "Resurrection."  

       "Apostle", Messenger, Herald - a person called by God, i.e., prompted by the understood, realized Truth of God's Will to serve the cause of evangelizing and establishing the Spirit of Truth in the minds of others. It is a righteous man to whom the "mysteries of Christ" are open, accessible, understandable. Such "apostles," the preachers of the Truth of God's Word, were the twelve disciples of Jesus Christ.

The disciples of Jesus Christ were "apostles", messengers of the Truth - the true Forerunners and Prophets.