1. Lumen Gentium #20

The divine mission, entrusted by Christ to the apostles, will last until the end of the world (Mt. 28:20)...For they not only had helpers in their Ministry, but in order that their mission assigned to them might continue after their death, they passed on to their immediate co operators, as a kind of testament, the duty of perfecting and consolidating the work begun by themselves, charging them to attend to the whole flock in which the Holy Spirit placed them to shepherd the Church of God. (Acts 20:26)