Again a small snip from Who Shall Ascend?:
[Emphasis in original]
All those who do not believe in the Doctrine of Exclusive Salvation present two main obstacles-we should say, two main subterfuges: the one is two alternate forms of Baptism, "baptism of desire," and "baptism of blood," the other, invincible ignorance. We shall discuss these in turn. Before doing so, however, we repeat that no postulate may in any way be allowed to compromise the absoluteness of the Doctrine of Exclusive Salvation; on the contrary, this doctrine must be our touchstone and point of reference.
We must study the following canons of the Decrees of the Council of Trent:
1. "If anyone say that real and natural water is not necessary for baptism, and thus distort those words of our Lord Jesus Christ: 'Unless a man be born again of water and the Holy Ghost' [Jn. 3:5]., let him be anathema." (Canon 2, Session VII. Denz. 1615).
2. "If anyone say that Baptism is optional [liberum], and is not necessary for salvation, let him be anathema." (Canon 5. Ibid, 1618).
3. "In these words the description of the justification of the sinner is given as being a translation from that state, in which man is born the son of the first Adam, into the state of grace and 'adoption of sons' [Rom. 8:151 of God, through the second Adam, Jesus Christ our Savior; which translation indeed cannot take place without the bath of regeneration [can. 5 de bapt.] or his wish (as it is written: 'Unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God' [Jn. 3:5])." (Sess. VI, Cap. 4. ¡bid, 1524).
The reader must take careful note of the three statements above. The difference between the first two and the third is quite great, and for very substantial reasons. The crux of the matter lies in the fact that the third statement is mainly concerned with justification, while the first two insist that sacramental Baptism is necessary for salvation. . . . . . .