The Greek apostolos is composed of apo, from, or away from; and stolos, an equipment, an expedition, whether by land or sea. It also carries with it the idea that an important message is associated with the sending: as in an ambassador, who is one charged with representing the authority of the person who sends. The word was therefore a very suitable one to apply to men who were given the commission to make in turn disciples of all the nations, to go into all the world and preach the gospel to the whole creation (Matt 28:19; Mark 16:15). To say an apostle simply means “one who is sent” is incorrect in how the New Testament uses it. The application of the term “apostles” varies in different parts of the New Testament. In the Gospels, it generally refers to the twelve disciples. In the earlier chapters of the Acts it refers to the Twelve who were personally chosen by Jesus of Nazareth to be his special companions, substituting Matthias for Judas Iscariot. They were the leaders of the church during its earliest days. Later, the term was applied to Paul and Barnabas, and, by implication, to James, the Lord’s brother (Gal 1:19). Besides these, the term is applied to Andronicus and Juniua, fellow prisoners with Paul, who he says were of note among the apostles (Rom 16:7). In another connection it is applied to certain officers in the early church, being placed before pastors and teachers (1 Cor 12:28; Eph 4:11).
The Origin of the Organic World – Part One