In Greek, the word disciple means “one who is taught.” Apostle, on the other hand, means “one who is sent,” as someone entrusted with a specific mission or purpose. Christ chose twelve men whom He first taught and then sent out into the world in order to spread His gospel teachings.
Although St. Paul was not one of the original Twelve, he was clearly sent forth by Christ and entrusted with a mission to evangelize the Gentile world. In our Lord’s own words, Paul became “a chosen instrument of mine to carry my name before the Gentiles and kings and the sons of Israel!” (Acts 9:15)
Paul also refers to himself as an apostle many times in the New Testament, and even defends his apostleship in his first letter to the Church in Corinth (1st Corinthians 9:1-2).
