"So that this call should resound throughout the world, Christ sent forth the apostles he had chosen, commissioning them to proclaim the gospel: 'Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you; and lo, I am with you always, to the close of the age.' Strengthened by this mission, the apostles 'went forth and preached everywhere, while the Lord worked with them and confirmed the message by the signs that attended it.'" (CCC 2)
"Those who with God's help have welcome Christ's call and freely responded to it are urged on by love of Christ to proclaim the Good News everywhere in the world. This treasure, received from the apostles, has been faithfully guarded by their successors. All Christ's faithful are called to hand it on from generation to generation, by professing the faith, by living it in fraternal sharing, and by celebrating it in liturgy and prayer." (CCC 3)