The Church is koinonia — an organic communion, a fellowship, a union of all: all races, all tax brackets, a communion in whom is neither Jew nor Greek, slave nor free person, male nor female as Paul beautifully described it (Gal 3:28). This means it’s a communion transcending every human distinction.

But the Church is also a communion with God the Trinity — Father, Son, and Holy Spirit. A communion, so to speak, both horizontal and vertical — it’s communion not only with our fellow human beings but also communion with God himself. That is, the communion that is the Church is sacramental. It’s communion both divine and human, immaterial and material. The Church is invisible, as well as visible; it has a visible structure. But its invisible structure is what’s triumphant and eternal, revealed in what’s materially made holy.

To stand before this communion is to stand mystically before Christ. To encounter the Church, the sacrament of Christ, is, therefore, a personal encounter. And if it’s a personal encounter, this Body of Christ communicates personally; that is, Christ speaks to us, in a sense, in his body, the Church. This is how we understand Scripture, tradition and revelation. Scripture is how the Body of Christ, the Church, speaks. When we encounter Scripture, that encounter is always mystical; it’s a coming into contact with the “mystery of Christ.” And it’s when we encounter Christ scripturally within the Body of Christ — the human and divine fellowship which is also called the Church — that we experience the event of revelation. Thus, as Catholics, our experience of the Bible is fundamentally a relational experience.

Because of this, what we’re talking about really is how to have a personal relationship with Jesus Christ. We Catholics believe that to have a personal relationship with Christ, a person must also have a relationship with him within the communion of the Church, the Body of Christ. This is where one finds the real Jesus with whom one can have a personal relationship, which brings salvation. For we Catholics, knowing Jesus personally and scripturally, and also living within the communion of the Church cannot be separated; to separate these truths is to render each false. This is a fundamental truth of Catholicism.

While Jesus, the Church, the Body of Christ, speaks to us in Scripture and tradition, so too we are communicated with: that is, in sacrament, the Sacraments — the sacred mysteries.

To talk about the sacraments, begin by thinking of the person you love — your wife or husband, a friend. How do you express your love? Do you simply use words? Do you simply say, “I love you”? Do you never hug, kiss, hold hands? When you express your love for another person, do you never express that love sensually? Of course, you do: you hug, kiss, hold hands and so on. Because that’s what love is — it’s more than words. And that, very plainly, is why we have not only Scripture, the words of God’s love, but also the sacraments, the sensual expression of God’s love. It’s really that simple.

But how are the sacraments sensual expressions of God’s love? A little basic theology is helpful here. Now the classic definition of a sacrament is simply this: A sacrament is an outward visible sign of an inward invisible grace. The sacrament of the Eucharist, for example, is an outward sign (bread and wine) or an inward invisible grace (the body and blood of Christ).

Now this is a perfectly good definition of a sacrament. But I find another definition helpful too: A sacrament is a sign, which participates in what it signifies. That is, again looking at the Eucharist, not only does the bread and wine signify Christ’s body and blood, the bread and wine actually participate in Christ’s body and blood — the bread and wine truly become the Body and Blood of Christ. In the sacraments, by the power of the Holy Spirit, Christ acts by means of visible signs to “make present efficaciously the grace that they signify” (Catechism of the Catholic Church, No. 1084). A stop sign, for instance, is simply a sign that relates a message: Stop! But it’s not a sign that participates in any sort of metaphysical form or being; there is no eternal being of stop-ness. A sacrament is a sign and more: it’s a sign that participates in what it signifies. And this definition can be applied to all the sacraments.

Before we look at the first sacrament, baptism, consider this story: I have a friend who’s a believer in Jesus but who’s never been baptized. Though he’s a good and faithful person, he didn’t grow up in a family or community that placed much importance on baptism. What mattered more, he thought, was your heart, your faith; as long as you loved Jesus and believed in him, it didn’t matter whether you went through some material ritual. The ritual is insignificant, he believed.

This is not an uncommon view. Many of our Protestant sisters and brothers think this. And it does certainly have logic and plausibility. It rightly emphasizes the priority of faith over works and over ritual. Yet, on the other hand, such a view is simply not biblical. It’s actually contrary to Scripture. How so? Well, one need only read Peter’s words in Acts of the Apostles where he said, “Repent and be baptized, every one of you, in the name of Jesus Christ” (Acts 2:38). This passage comes from Pentecost, where Peter gives this instruction at the end of his first sermon — the very first apostolic sermon in Christian history. Peter had just preached the Gospel of Jesus, moving the crowd to the threshold of faith. And in response, the people ask, “What are we to do?” And this was Peter’s answer: Repent and be baptized!

This, very simply, is why my friend’s view is unbiblical. This is why saying the ritual of baptism isn’t important is contrary to Scripture. Yes, my friend’s view bears a logic and plausibility; he does have a moral point. But he can’t say it’s a biblical point. From day one, as we’ll see, baptism has been put forward as a necessity for Christian believers. Since the very beginning, baptism was considered important, essential. That’s simply the testimony of Scripture, and it’s something we Catholics have always believed.

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.