"By combining material from various texts, scholars conclude that an apostle was one who had seen the risen Jesus and who had a personal commission from Jesus to proclaim the gospel. The number who could claim the title is not determined, but that the title was important is clear from Paul's insistence on his right to be called an apostle. If there are any officers of the Church in the New Testament, they are apostles. . .
The Greek word, apostolos, from which our English word "apostle" comes, means in classical Greek literature a naval expedition and, in later literature, a delegate or a messenger. There is no parallel in Greek to the religious use of the word; but in Judaism the corresponding Aramaic word was a title given to men sent from Jerusalem to Jewish communities abroad. This may have influenced the Christian use of the word." John L. McKenzie, Authority in the church, Sheed and Ward, 1966.
|Head of an apostle by Jean-Michel Moreau, public domain|