Objection 1. It seems that a character is imprinted by all the sacraments of the New Law: because each sacrament of the New Law makes man a participator in Christ's Priesthood. But the sacramental character is nothing but a participation in Christ's Priesthood, as already stated (3,5). Therefore it seems that a character is imprinted by each sacrament of the New Law.
Objection 2. Further, a character may be compared to the soul in which it is, as a consecration to that which is consecrated. But by each sacrament of the New Law man becomes the recipient of sanctifying grace, as stated above (Question 62, Article 1). Therefore it seems that a character is imprinted by each sacrament of the New Law.
Objection 3. Further, a character is both a reality and a sacrament. But in each sacrament of the New Law, there is something which is only a reality, and something which is only a sacrament, and something which is both reality and sacrament. Therefore a character is imprinted by each sacrament of the New Law.
On the contrary, Those sacraments in which a character is imprinted, are not reiterated, because a character is indelible, as stated above (Article 5): whereas some sacraments are reiterated, for instance, penance and matrimony. Therefore not all the sacraments imprint a character.
I answer that, As stated above (62, 1,5), the sacraments of the New Law are ordained for a twofold purpose, namely, as a remedy for sin, and for the Divine worship. Now all the sacraments, from the fact that they confer grace, have this in common, that they afford a remedy against sin: whereas not all the sacraments are directly ordained to the Divine worship. Thus it is clear that penance, whereby man is delivered from sin, does not afford man any advance in the Divine worship, but restores him to his former state.
Now a sacrament may belong to the Divine worship in three ways: first in regard to the thing done; secondly, in regard to the agent; thirdly, in regard to the recipient. In regard to the thing done, the Eucharist belongs to the Divine worship, for the Divine worship consists principally therein, so far as it is the sacrifice of the Church. And by this same sacrament a character is not imprinted on man; because it does not ordain man to any further sacramental action or benefit received, since rather is it "the end and consummation of all the sacraments," as Dionysius says (Eccl. Hier. iii). But it contains within itself Christ, in Whom there is not the character, but the very plenitude of the Priesthood.
But it is the sacrament of order that pertains to the sacramental agents: for it is by this sacrament that men are deputed to confer sacraments on others: while the sacrament of Baptism pertains to the recipients, since it confers on man the power to receive the other sacraments of the Church; whence it is called the "door of the sacraments." In a way Confirmation also is ordained for the same purpose, as we shall explain in its proper place (65, 3). Consequently, these three sacraments imprint a character, namely, Baptism, Confirmation, and order.
Reply to Objection 1. Every sacrament makes man of the a participator in Christ's Priesthood, from the fact that it confers on him some effect thereof. But every sacrament does not depute a man to do or receive something pertaining to the worship of the priesthood of Christ: while it is just this that is required for a sacrament to imprint a character.
Reply to Objection 2. Man is sanctified by each of the sacraments, since sanctity means immunity from sin, which is the effect of grace. But in a special way some sacraments, which imprint a character, bestow on man a certain consecration, thus deputing him to the Divine worship: just as inanimate things are said to be consecrated forasmuch as they are deputed to Divine worship.
Reply to Objection 3. Although a character is a reality and a sacrament, it does not follow that whatever is a reality and a sacrament, is also a character. With regard to the other sacraments we shall explain further on what is the reality and what is the sacrament.
Source: Summa Theologica (New Advent)