In chapters 5 through 8 of his Letter to the Romans, St. Paul offers a beautiful description of baptized life. Reading through those chapters will teach you all you need to know about baptism. Here are the salient points.

After Paul talks about faith in Christ — how when we have faith in Christ, hope is given and the Holy Spirit is “poured into our hearts” (Rom 5:5) — he talks about baptism. And the first thing he does, echoing the Gospels, is to identify baptism with the death and resurrection of Jesus. He writes, “We were indeed buried with him through baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, we too might live in newness of life” (Rom 6:4). This means, quite simply, that the believer’s death is bound to Jesus’s death, and Jesus’ resurrection is, in turn, shared with the believer. “For if we have grown into union with him through a death like his, we shall also be united with him in the resurrection” (Rom 6:5). By faith and by baptism, we unite ourselves to Christ. In this way, his death becomes ours and his resurrection becomes ours, too. In other words: Jesus’s destiny becomes our destiny. His trajectory becomes our trajectory, so to speak. Thus, when we come to our death, it’ll be Jesus’ death, too. And his resurrection becomes ours. To quote the Eucharistic Preface prayed at funerals, for the faithful, “life is changed not ended” (Roman Missal, Preface I for the Dead). And that’s because, having died with Christ in baptism, we live with him in resurrection.

But this attachment to Jesus begun in baptism is also moral. This means that not only is the believer’s death united with Christ’s death, and not only is his resurrection shared with the believer, but the morality of Jesus becomes the believer’s morality. Forgiven of their sins, believers take on Jesus’ values and vision (Col 2:12-13). Very quickly after Paul talks about the theological reality of baptism, he begins to talk about the moral reality of baptism, about what “newness of life” means (Rom 6:4). For the baptized, “sin must not reign.” The baptized must not “obey their desires.” The bodies of the baptized are no longer to be “weapons for wickedness” but “weapons for righteousness,” because sin should no longer have any power over believers (Rom 6:12-14).

This doesn’t mean believers know nothing of moral struggle. Baptism allows for moral struggle — one need only read Romans 7 to see this. What Paul is saying in this passage has been interpreted in various ways. However, one way to read it — as St. Augustine and also the Catholic Church came to read it — is to read Paul’s words autobiographically. That is, it’s likely Paul here is speaking about what we call “concupiscence,” about the internal conflict between the law of God and the law of flesh — two laws at war in each of us, a battle fought within us even after baptism. “I discover the principle that when I want to do right, evil is at hand. For I take delight in the law of the God, in my inner self, but I see in my members another principle as war with the law of my mind” (Rom 7:22-23). It’s a war each of us knows, a war that goes on our whole life long, but which has an end in Christ’s eternal mercy. Baptism doesn’t remove this war from believers, nor does it magically remove our freedom. Rather, this passage explains how baptism offers hope to the moral struggle, reminding us who will ultimately win the believer’s moral battles — not the believer, but Christ in the believer. “Miserable one that I am! Who will deliver me from this mortal body? Thanks be to God through Jesus Christ our Lord,” Paul cried out (Rom 7:24-25).

What we’re talking about here is what the Church calls “original sin,” which is only sin in an analogous sense. Original sin names simply the just state of affairs pertaining to humankind after the first sin of our first parents, Adam and Eve. It simply refers to the fact that because of human sin we are justly incapable of holiness — incapable of heaven, so to speak. Through baptism, Christ, however, removes that incapacity. But it doesn’t remove either our weakness or freedom. Concupiscence remains; the moral battle still rages — but now with hope. As the Catechism of the Catholic Church puts it, “Baptism, by imparting the life of Christ’s grace, erases original sin and turns a man back toward God, but the consequences for nature, weakened and inclined to evil, persist in man and summon him to spiritual battle” (No. 405).

Baptism gives the believer the grace — that is, the Spirit — necessary for real moral growth. With baptism, the believer is given both the opportunity and the grace to win the moral fight; that is, the condemnation of original sin is removed, and the Spirit is given. “Hence, now there is no condemnation for those who are in Christ Jesus,” Paul writes. He’s talking about the baptized, those “in Christ.” Christ condemned “sinful flesh” by assuming its likeness, by means of his death and resurrection. And, by the gift of the Holy Spirit, those who are baptized can “live according to the spirit with the things of the spirit” (Rom 8:1-5). What baptism does for the believer is it opens a new spiritual and moral horizon. It doesn’t eliminate from the believer’s moral struggle at all, but it offers the believer hope, the promise that sin won’t win in the end. For me, I’ve always been comforted by this, and by the fact that this was written by an apostle. I’ve also always found comfort in the Church’s teaching about original sin and concupiscence because it’s realistic, yet hopeful. If Paul can struggle morally yet still hope and still go on, then so can I. And so can you.

To summarize the basic theology of baptism: In baptism, we are united to Christ; we are in Christ. As Paul wrote to the Galatians, “no longer I, but Christ lives in me” (Gal 2:20). We share in Christ’s life; we become sons and daughters of the Father, each of us in the Son. As the writer to the Hebrews put it, that’s why Jesus is not ashamed to call us “brothers,” because we have been consecrated in Christ and now share his “origin” (Heb 2:11). This explains Paul’s beautiful words in the letter to the Romans, at the end of his chapters on baptism, about believers’ unbreakable union with Christ. “Who will separate us from the love of Christ?” Paul asks. Anguish? Distress? Persecution? No, nothing will. Not even an angel nor any other power “will be able to separate us from the love of God in Christ Jesus our Lord” (Rom 8:35-39). This is not sentimental gibberish but pure theology. What makes it possible for Paul to say that nothing will separate us from the love of Christ is baptism. These are not empty feel-good words. Only in faith and baptism is this passage made real for the Christian. This is the truth that made martyrs brave and fearless of death. Fearless, because they knew they couldn’t be separated from Christ. Which also, as a rather significant aside, is why a Christian is baptized once because the union made in baptism is so perfect and unbreakable (cf. Eph 4:5).

This is why the Catechism says that baptism is “the basis of the whole Christian life, the gateway to life in the Spirit.” Because it’s very much a birth into new life. It’s a true spiritual regeneration and the “door to the other sacraments,” which we’ll explore as this series progresses (Catechism, No. 1213). For now, it suffices here to say simply that this is how the Christ who through his body, the Church, and through the Scripture and Tradition not only speaks to us but now touches us — through water and Holy Spirit.

Father Joshua J. Whitfield is pastor of St. Rita Catholic Community in Dallas and author of “The Crisis of Bad Preaching” (Ave Maria Press, $17.95) and other books. Read more from the series here.