You ask how I prove this? From the very words of the Lord! We can make no exceptions where no disctinction is made.

       Many over the years -both liberal Catholic and Protestant- have denied either the literal meaning of this verse and/or its all-inclusive meaning, that is, its universality. So they, by definition of their status, reject the teaching of Popes and the Church anyway. Therefore we will examine this and a few related texts of Sacred Scripture.

       I should first point out that you should notice that Christ says we must be "born of water and the Spirit" immediately following His statement that we must be "born again" or "born from above." He was thus explaining how this spiritual rebirth was to come about -by actual water and the Spirit. Nevertheless, some Protestants, in denying this by ignoring the fact just pointed out, say that the verse immediately following verse five explains what being "born of water and the spirit" means. Verse six:

That which is born of the flesh, is flesh; and that which is born of the Spirit, is spirit.

       First: Verse six can't be explaining verse five because in verse six the Lord Jesus is contrasting flesh and Spirit pointing out that they are contrary to one another. Whereas in verse five Jesus is uniting "water and the Spirit," declaring a union betweeen the two. This doesn't make sense if verse six was explaining verse five. In verse six flesh and Spirit are seen as opposed, one is the antithesis to the other. In verse five water and the Spirit are spoken of in concert with each other. The word "and" is a conjunction uniting the two, not contrasting them. So a verse (six) that specifically contrasts two things and sees them in opposition to each other cannot be explaining a previous verse (five) that speaks of similar things not at all opposed, but as united and conjoined.

       This truth is further buttressed by the fact that elsewhere in St. John's Gospel water is NEVER contrasted with the Spirit and the spiritual life. On the contrary, the two are in unison (see Jn. 4:14; 7:38-39). God did not inspire His authors to employ usages which are contradictory.

       Second: As just pointed out, when the Lord Jesus declared that, to enter the kingdom of God we must be "born of water and the Spirit," He was in fact explaining how one must be born again in order to enter the kingdom of God. Christ was answering Nicodemus' question of how one can be born a second time by saying one must be born of BOTH "water and the Spirit." In other words, our SECOND birth is "OF WATER and the SPIRIT." This is the obvious and plain sense of these verses. Any other meaning is a clear exercise in grammatical and logical gymnastics which will have you landing on your face.

       Third: If the word "water" of verse five means simply our natural/fleshly birth (amniotic fluid?) why would the Lord Jesus immediately after His discourse go and have His apostles baptize with water? Why would He try to demonstrate our natural birth, which everyone already knows about, and not demonstrate our spiritual re-birth, since this was the very point and focus of the Lord's teaching (see 3:7). Did Jesus suddenly become a biology teacher and not a teacher of heavenly and salvific truths? In explaining how one is to have a second birth it is so obvious that one must have a first birth before their second birth that the mere mentioning of it is idiotic. (Surely Christ was not attempting to instruct someone who had not yet been born!)

       Fourth: If water was meant metaphorically then "Spirit" should also be meant metaphorically. This is so because Christ never used a symbolic term in conjunction with a literal term in the same sentence, especially where the two are used as a union as in this case. This would be terribly misleading in either modern English idiom or in the Hebraic idiom of the first century. Also, how could the word "Spirit" be used to stand for something other than Spirit? The Lord Jesus always meant the word "Spirit" literally. And if He didn't mean "water" literally but only metaphorically, why did the Lord immediately go to real, literal (!), water and have His disciples baptize with that literal water? In fact, God reveals in Jn.3:23 that the two -water and baptism- are identified together. None of this would make sense unless the Lord Jesus meant "of water" to mean actual water and that this was in reference to baptism (as is made clear in Jn.3:23).

       The actions of the Lord Jesus immediately following His conversation with Nicodemus demonstrate that He meant "water" literally; for He and the apostles then proceeded to baptize with water (see Jn.3:22-23, 26). An action by Christ immediately after a teaching demonstrates what He meant by His teaching. Water, then, was meant literally, and is a reference to baptism. If this is not the case, then, His actions immediately following this teaching were terribly misleading and self-contradictory -a blasphemous option.

       At the dogmatic Council of Trent (Session VII, March, 1547) the Catholic Church infallibly defined as a matter of divine and Catholic Faith:

If anyone says that true and natural water is not necessary for baptism and thus twists into some metaphor the words of our Lord Jesus Christ: "Unless a man be born again of water and the Holy Spirit" (Jn. 3:5): let him be anathema. (Canon 2, "On Baptism;" Denz. 858)

If anyone says that baptism is optional, that is, not necessary for salvation, let him be anathema. (Canon 5, "On Baptism;" Denz.861)

ST. PAUL AND THE CORINTHIANS

       Some Protestants (and liberal "Catholics") also point out that, if baptism is essential for salvation, then why didn't the Apostle Paul attempt to baptize more people than he did? Or why, in his first letter to the Corinthians (see 1 Cor.1:10-17), did he (seemingly) down play the role of Baptism and confess that he was glad he didn't baptize any (except maybe a few)? We will answer this.

       First of all St. Paul was trying to emphasize that he received the specific calling to preach the Gospel and bring people to believe in Jesus Christ. This is quite important because faith, which results from hearing the preaching of the Gospel (Rom. 10: 14,17), is a necessary pre-requisite for the reception of Baptism -just as Christ Jesus taught (see Mat.28:19; Mk.16:16). The Gospel must be preached so that faith could be first established. St. Paul's job, then, was to bring people to the point of repentance, belief, and readiness to receive the forgiveness of sins and the grace of Christ in Baptism.

       Second, the context of the whole situation reveals that St. Paul was not really down playing the importance of Baptism itself. Read carefully; he was addressing a number of schisms and their cause. He was responding to a pastoral crisis where there were members of the Church in Corinth who were claiming to be followers of those who brought them to Christ and baptized them (i.e., Paul, Apollos, Cephas, etc.). St. Paul's point is directed towards these divisions. This is why he says he is glad he didn't baptize them (except Crispus, Gaius, and the household of Stephanas) for the very reason that they would all want to claim to be following him -as those few mentioned above must have- and not Jesus Christ.

       In other words, St. Paul said what he said concerning Baptism specifically because he did not want to be the occasion for any of these divisions and factions. This is why he says "so that no man should be baptized in my name" (vs.15).

       St. Paul, then, was in reality down playing the MINISTERS of Baptism and addressing the divisions resulting from some confessional adherence to them; he was not down playing Baptism itself. St. Paul wanted them to focus on Christ, not on the ministers: "I planted [preached], Apollos watered [baptized], but God was causing the growth. So then neither the one who plants nor the one who waters is anything, but God causes the growth... we are God's fellow workers... [yet] let no one boast in men... you belong to Christ"(see 1 Cor.3:6-7, 9, 21, 23). He then says that men should "regard us as servants of Christ, and stewards of the mysteries of God" (4:1). The name or greatness of those who administer Baptism is not at all important. What is important is the action of God who "causes the growth," which is what makes Baptism significant. Thus, Baptism receives its efficacy from God because it is an action of God as revealed here, but done through men -members of the Body of Christ.
       In fact, we know St. Paul thought extremely high of Baptism and the realities it brings about because of what God inspired him to teach in his other letters (see Rom.6:3f; Gal.3:27; Eph.4:5; 5:26; Col.2:12; Titus 3:5-6). Later on in this very same letter to the Corinthians St. Paul writes about a very significant aspect of Baptism: we (who are baptised) were baptised into one body (see 12:13). He shows its importance by teaching that it is Baptism itself which brings unity to individuals by making us one body in Christ.

       Interestingly this very situation by implication undermines what those who deny the necessity of Baptism say when they put forth that Baptism is down played here. If Baptism wasn't essential and necessary, then why did these young Christians hold in such high regard and veneration those who baptized them -to the point where they gave a type of allegiance to them? Why would they cause quarrels, and even divisions and schisms directly related to who baptized them, unless they were taught the great importance of Baptism and its necessity for salvation? Why didn't St. Paul simply tell them flat-out that baptism wasn't necessary for salvation or wasn't important enough to be the occasion for division? But he never stated such a belief, nor used that line of reasoning to correct them. Therefore, this exact situation butresses the Catholic position, for the schisms would not have occurred if they were not taught the great significance and necessity of Baptism.

       Nowhere, when addressing this specific problem here, does St. Paul actually address Baptism itself, and this indicates that he didn't want to undermine its value and necessity. No where does he deny the implied importance of Baptism that these Christians must have had in regard to it as a cause for division. Surely he would have told them that Baptism wasn't THAT important for it to cause division and strife. Yet he didn't at all minimize the importance and necessity of Baptism. He only minimized those who ministered it as his way of correcting the schisms. Paul was extremely careful here on maintaining the proper focus in regards to healing these divisions. These points all support the Catholic position on Baptism and its necessity for salvation.

       Another significant point to think about is this: maybe it was precisely because St. Paul did not baptize many of those to whom he preached that he often had to express and defend his authority and apostleship (see 1 Cor.2:1-4; 9:1f; 15:9-10; 2 Cor.3:1f; 10:8f; 11:5f; 12:1f, 11-12, etc.), for Baptism was recognized as being inseperable from evangelization and the conversion process (Paul had others with him, such as Apollos, to baptized those who repented and believed): "Go, therefore, teach all nations, baptizing in the name..."(Matt.20:19); "Do penance AND be baptized every one of you...(Acts.2:38); "He who believes AND is baptised shall be saved..."(Mk.16:16). Thus, the entire episode reveals just the opposite of what those who deny the salutary importance of Baptism maintain, for the crisis was based in part upon the its presumed importance.

       This text from First Corinthians, Chapter 1, then, does not undermine the Catholic position in regards to Baptism, but actually supports it. This is, of course, consistent with Christ's teaching as recorded in the Gospel of St. John: that no one can enter the kingdom of God unless he is born again of water and the Spirit. Any position different would be a watering down of the plain meaning of Christ's Word.