During his ministry Jesus appointed the twelve apostles to continue his Work.
‘And he went up on the mountain and called to him those he himself wanted. And they came to him. Then he appointed twelve, that they might be with him and that he might sent out to preach and to have power to heal the sicknesses and to cast out demons.’ (Mk 3:13-14)
An apostle, being one of the twelve apostles, was therefore someone close to the Lord who was called by Him, sent out (apo-stello) into the world to proclaim the Gospel through preaching, teaching and bearing witness to the Kingdom of God through miracles in the Holy Spirit.
These twelve Jesus sent out, instructing them, “Go nowhere among the Gentiles and enter no town of the Samaritans, but go rather to the lost sheep of the house of Israel. And proclaim as you go, saying, ‘The kingdom of heaven is at hand.’ Heal the sick, raise the dead, cleanse lepers, cast out demons. You received without paying; give without pay. (Mt 10:5-8) …Holy Orders