Chapter 15 — Part II: The Sacraments — Introduction on the Sacraments in General
Section 50. Among them three are said to be necessary beyond the rest, although in all three this necessity is not of the same kind. The universal and absolute necessity of Baptism our Saviour has declared in these words: Unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God. Penance, on the other hand, is necessary for those only who have stained themselves after Baptism by any mortal guilt. Without sincere repentance, their eternal ruin is inevitable. Orders, too, although not necessary to each of the faithful, are of absolute necessity to the Church as a whole.