Reply Obj. 1: Even before Christ's Passion, Baptism, inasmuch as it foreshadowed it, derived its efficacy therefrom; but not in the same way as the sacraments of the Old Law. For these were mere figures: whereas Baptism derived the power of justifying from Christ Himself, to Whose power the Passion itself owed its saving virtue.
Reply Obj. 2: It was not meet that men should be restricted to a number of figures by Christ, Who came to fulfil and replace the figure by His reality. Therefore before His Passion He did not make Baptism obligatory as soon as it was instituted; but wished men to become accustomed to its use; especially in regard to the Jews, to whom all things were figurative, as Augustine says (Contra Faust. iv). But after His Passion and Resurrection He made Baptism obligatory, not only on the Jews, but also on the Gentiles, when He gave the commandment: "Going, teach ye all nations."
Reply Obj. 3: Sacraments are not obligatory except when we are commanded to receive them. And this was not before the Passion, as stated above. For our Lord's words to Nicodemus (John 3:5), "Unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God, seem to refer to the future rather than to the present." _______________________
THIRD ARTICLE [III, Q. 66, Art. 3]
Whether Water Is the Proper Matter of Baptism?
Objection 1: It seems that water is not the proper matter of Baptism. For Baptism, according to Dionysius (Eccl. Hier. v) and Damascene (De Fide Orth. iv), has a power of enlightening. But enlightenment is a special characteristic of fire. Therefore Baptism should be conferred with fire rather than with water: and all the more since John the Baptist said when foretelling Christ's Baptism (Matt. 3:11): "He shall baptize you in the Holy Ghost and fire."
Obj. 2: Further, the washing away of sins is signified in Baptism. But many other things besides water are employed in washing, such as wine, oil, and such like. Therefore Baptism can be conferred with these also; and consequently water is not the proper matter of Baptism.
Obj. 3: Further, the sacraments of the Church flowed from the side of Christ hanging on the cross, as stated above (Q. 62, A. 5). But not only water flowed therefrom, but also blood. Therefore it seems that Baptism can also be conferred with blood. And this seems to be more in keeping with the effect of Baptism, because it is written (Apoc. 1:5): "(Who) washed us from our sins in His own blood."
Obj. 4: Further, as Augustine (cf. Master of the Sentences, iv, 3) and Bede (Exposit. in Luc. iii, 21) say, Christ, by "the touch of His most pure flesh, endowed the waters with a regenerating and cleansing virtue." But all waters are not connected with the waters of the Jordan which Christ touched with His flesh. Consequently it seems that Baptism cannot be conferred with any water; and therefore water, as such, is not the proper matter of Baptism.
Obj. 5: Further, if water, as such, were the proper matter of Baptism, there would be no need to do anything to the water before using it for Baptism. But in solemn Baptism the water which is used for baptizing, is exorcized and blessed. Therefore it seems that water, as such, is not the proper matter of Baptism.