Let us begin by looking at (one popular translation of) the critical passage (I reference the older Enchiridion Symbolorum numbers throughout).
(796) "In these words a description of the justification of a sinner is given as being a translation from that state in which man is born a child of the first Adam to the state of grace and of the “adoption of the sons” [Rom. 8:15] of God through the second Adam, Jesus Christ, our Savior; and this translation after the promulgation of the Gospel cannot be effected except through the laver of regeneration [can. 5 de bapt.], or a desire for it, as it is written: “Unless a man be born again of water and the Holy Spirit, he cannot enter into the kingdom of God” [John 3:5]."
The Latin :
"Caput 4. Insinuatur descriptio justificationis impii, et modus ejus in statu gratiæ
Quibus
verbis justificationis impii descriptio insinuatur, ut sit translatio
ab eo statu, in quo homo nascitur filius primi Adæ, in statum gratiæ
et »adoptionis filioram«
Dei, per secundum Adam Jesum Christum Salvatorem nostrum; quæ quidem
translatio post Evangelium promulgatum sine lavacro regenerationis
aut ejus voto fieri non potest, sicut scriptum est: »Nisi quis
renatus fuerit ex aqua et Spiritu Sancto, non potest introire in
regnum Dei"The Latin :
"Caput 4. Insinuatur descriptio justificationis impii, et modus ejus in statu gratiæ
We notice right away that the translation “except through” is not a literal rendering of the Latin sine (which means literally “without”). So let us now consider the critical words in literal translation: “justification … cannot happen without the laver of regeneration (=Sacramental Baptism) or a desire for it” (translatio [=justificatio] … sine lavacro regenerationis aut eius voto fieri non potest). I’ve seen proponents of BoD render this phrase as “without EITHER the laver of regeneration OR ELSE the desire for it”. But there’s no explicit “EITHER” here at all, which in Latin would require a second aut (sine AUT lavacro regenerationis AUT eius voto).
Now let’s look at the word translated as “desire”. In Latin it’s voto (a form of votum). Votum does not refer to a simple “desire” (or “wish” or “longing”) but is a much stronger word. It derives from the Latin word for a “vow” or solemn intention and is linguistically related to the word for “will” (volo). Notice the linguistic root vo- (volo (to will), voluntas (the will), votum). So the word votum actually refers to the will. I hereafter replace the word “desire” with “will”. I’ll come back to this notion of “will” when I discuss the entire context of Trent.
Now, having put aside this (deliberately?) misleading translation, let us consider the actual meaning of this passage. If someone were to say (“We cannot play baseball without a bat or a ball.”), you could take that in one of two ways. 1) We can play baseball with one OR the other (but do not require both). 2) We can play baseball only if we have both. If the first meaning had been intended, one would expect an emphatic EITHER … OR (ELSE) to make it clear. We cannot play baseball without EITHER a bat OR ELSE a ball. And that’s why some BoD proponents actually insert an “ELSE” into their rendering (a word which is not there in the original Latin); they do so in order to impose their own interpretation on the passage.
Why wouldn’t the person just say (“We cannot play baseball without a bat and a ball.”)? Well, in a double-negative grammatical construction such as “cannot without”, the disjunctive “or” actually emphasizes that BOTH are required in that if one OR the other were absent, baseball cannot be played. In other words, were the double negative to be rendered as its positive equivalent, the “or” would become an emphatic “and”.
So did the Council of Trent use an ambiguous phrase here? Well, only if you don’t consider the immediate context (i.e. the very next passage). Let’s return to the baseball example. “We cannot play baseball without a bat or a ball, for John said that we need a bat and a ball to play baseball.” Now, suddenly the immediate context disambiguates the phrase. So let’s return to Trent (I paraphrase the second part in order to illustrate my point): “Justification cannot happen without the laver or the will for it, for Jesus taught that water AND the Holy Spirit are required.” Trent makes the following analogy—laver:water::will:Holy Spirit (laver is to water as will is to the Holy Spirit). We’ll come back to that analogy later to show how Trent returns to it over and over again in its teaching.
So, in order to interpret Trent as teaching that this passage refers to an EITHER … OR would be to say that the phrase (“We cannot play baseball without a bat or a ball, for John said that we need a bat and a ball to play baseball.”) really means that we can play baseball if we have either a bat or a ball. And that’s utterly absurd. So once we cut away the bad translation and look at the immediate context, Trent clearly teaches that BOTH water Baptism AND the will for it are required for justification.
OK, so why would Trent go out of its way to indicate that you need Baptism AND the will to receive it? Doesn’t that seem obvious and superfluous to teach? On the contrary ! Keep in mind that Trent was addressing the Protestant heresies.
(792a) "Since at this time not without the loss of many souls and grave detriment to the unity of the Church there is disseminated a certain erroneous doctrine concerning justification …"
Protestants denied the need for a cooperation of the will with grace in the process of justification. We see a recurrent theme in the teaching of Trent, the need for cooperation of the will with grace.
(797) "the beginning of that justification must be derived from the predisposing grace [can. 3] of God through Jesus Christ, that is, from his vocation, whereby without any existing merits on their part they are called, so that they who by sin were turned away from God, through His stimulating and assisting grace are disposed to convert themselves to their own justification, by freely assenting to and cooperating with the same grace [can. 4 and 5], in such wise that, while God touches the heart of man through the illumination of the Holy Spirit, man himself receiving that inspiration does not do nothing at all inasmuch as he can indeed reject it, nor on the other hand can he [can. 3] of his own free will without the grace of God move himself to justice before Him."
So one paragraph after the key phrase under discussion here, Trent emphasizes that grace AND free will are required to be moved to “justice” (=justification), that you cannot arrive at justification without BOTH. Notice how grace alone does not suffice (“man … does not do nothing at all inasmuch as he can reject it”) nor does will alone suffice (“nor on the other hand can he of his own free will without the grace of God”). Notice how Trent teaches that Holy Spirit inspires that cooperation of the will in its disposition towards justification. Now hearken back to the analogy from just a paragraph earlier—laver:water::will:Holy Spirit.
Now let’s consider a couple of the related canons.
(812) "Can. 2. If anyone shall say that divine grace through Christ Jesus is given for this only, that man may more easily be able to live justly and merit eternal life, as if by free will without grace he were able to do both, though with difficulty and hardship: let him be anathema" [cf. n. 795, 809]
(814) "Can. 4. If anyone shall say that man’s free will moved and aroused by God does not cooperate by assenting to God who rouses and calls, whereby it disposes and prepares itself to obtain the grace of justification, and that it cannot dissent, if it wishes, but that like something inanimate it does nothing at all and is merely in a passive state: let him be anathema" [cf. n. 797].
So Trent emphasizes and teaches dogmatically that neither free will without grace, nor grace without free will are sufficient in the process of justification. That’s why Trent taught that we cannot be justified without the laver or the will, because both the laver AND the will are required for justification.
Trent taught that the Holy Spirit inspires the will to predispose and prepare it for justification, and that justification itself happens as a grace through Baptism.
(799) "Justification itself follows this disposition or preparation … through the voluntary reception of the grace and gifts. … The causes of this justification are: … the instrumental cause is the sacrament of baptism."
Notice again this phrase, the “voluntary reception of the grace [of Baptism]”, hearkening back to the teaching that both the will AND Baptism are required for justification, so that if a person isn’t properly disposed at Baptism, Baptism doesn’t as it were magically and passively put the person into a state of justification. Recall how the words voluntas (->voluntary) and votum are linguistically related. So that the votum, the so-called “Baptism of Desire” keyword, actually refers to this “voluntary reception of” Baptism, the cooperation of the will in this process of justification.
Now, if Trent had truly intended to teach BoD and the “three [so-called] baptisms”, then one would have certainly expected at least a token mention of Baptism of Blood (BoB). Trent’s silence regarding BoB further indicates that Trent had absolutely no intention of teaching about the “three baptisms” here.
Finally, one could actually read Trent as positively excluding BoD, for Trent lists the intention to receive Baptism among the “dispositions” or “preparation” for Baptism.
(798) "Now they are disposed to that justice [can. 7 and 9] when, aroused and assisted by divine grace, receiving faith “by hearing” [Rom. 10:17], they are freely moved toward God, believing that to be true which has been divinely revealed and promised [can. 12 and 14], and this especially, that the sinner is justified by God through his grace, “through the redemption which is in Christ Jesus” [Rom. 3:24], and when knowing that they are sinners, turning themselves away from the fear of divine justice, by which they are profitably aroused [can. 8], to a consideration of the mercy of God, they are raised to hope, trusting that God will be merciful to them for the sake of Christ, and they begin to love him as the source of all justice and are therefore moved against sins by a certain hatred and detestation [can. 9], that is, by that repentance, which must be performed before baptism [Acts 2:38]; and finally when they resolve to receive baptism, to begin a new life and to keep the commandments of God."
So this “resolve” to receive Baptism (rendered in Latin by the verb propono, to “propose” or “intend”) Trent lists among the “dispositions” section in PREparation for justification. Then Trent declares, as cited above,
(799) "Justification itself follows this disposition or preparation … through the voluntary reception of the grace and gifts. … The causes of this justification are: … the instrumental cause is the sacrament of baptism."
So justification itself only FOLLOWS the dispositions or PREparations (for the Sacrament of Baptism)—which dispositions include the resolution to receive Baptism.
In conclusion, the Council of Trent does NOT teach that we can be justified by laver of regeneration OR the will for it, but rather—against the Protestant heresies–that both the grace of Baptism (the laver) AND cooperation of the WILL are required for justification.