Are the sacraments instituted by our Blessed Lord necessary for obtaining the grace which corresponds to each one in particular, or is the receiving of these sacraments of counsel only?
These sacraments are absolutely necessary, in this sense, that if through one's own fault one neglects to receive them, one will not receive the grace corresponding thereto; and there are three of them which produce a certain effect such as can never come to be unless the sacrament be received (LXV. 4).
What are these three, and what is this certain effect dependent upon them?
They are Baptism, Confirmation, and Holy Orders; and the effect spoken of is the character which each of these sacraments impresses on the soul (LXIII. 6).
What is this character?
It is a certain quality of the spiritual order, constituting in the higher and intellectual part of the soul a sort of power or faculty which effects that he who receives it participates in the priesthood of Jesus Christ (LXIII. 1-4.).
Is this character impressed on the soul indelible?
Yes, it will remain for ever once it is received, to the glory of those who reach heaven who have therefore shown themselves worthy to bear it; and to the confusion of those in hell who have misused it (LXIII. 5).
Which character marks men according to the likeness of our Lord and makes them able to participate in His priesthood?
The sacrament of Baptism (LXIII. 6).
Next - The Catechism of the Summa - Tertia Pars - XXV. OF THE SACRAMENT OF BAPTISM: OF ITS NATURE; OF THE MINISTER OF THIS SACRAMENT (A)