The question is important, because it lies at the heart of Jesus’s explanation of “born again,” of new birth, of regeneration. When Jesus first introduces the category (John 3:3), Nicodemus clearly doesn’t understand what Jesus means (3:4 NIV): “How can someone be born when they are old?” he asks. “Surely they cannot enter a second time into their mother’s womb to be born!”

Many people think the question Nicodemus poses shows that he is a rather dimwitted literalist. But that’s almost certainly too harsh. You don’t get to be called “the teacher of Israel” (John 3:10—possibly a title) if you can’t spot the odd metaphor. When he hears Jesus say that to enter the kingdom one must be “born again,” I suspect Nicodemus understands Jesus to mean that we are not good enough to enter the kingdom: we must start over, have a different origin, spring from a different life. Nicodemus thinks Jesus is going too far: people can’t really start over or claim a new life, boast of a new birth, or enjoy a new beginning. Omar Khayyam had it right: “The Moving Finger writes; and, having writ, / Moves on: nor all thy Piety nor Wit / Shall lure it back to cancel half a Line, / Nor all thy Tears wash out a Word of it.”

Most of us have faced moments when we wish we could “start over,” or at least expunge some of our worst sins and faults. “Oh, for a man to arise in me / That the man I am may no longer be,” Alfred Lord Tennyson wrote. Or, as John Clare said, “If life had a second edition, how I would correct the proofs.” Nicodemus perceives the futility of insisting that we must have a new beginning: it’s a bit late to demand a new beginning when we’ve made such a mess of the voyage (John 3:4, 9). And if that’s what is required to get into the kingdom, there is no hope: “How can someone be born when they are old?”

But far from backing down, Jesus repeats the point (John 3:5), yet he does so in such a way that he expands on “born again,” turning it into “born of water and the Spirit,” and thus provides some explanation. That’s why it is so important to understand what Jesus means by this expression.

So what does he mean?

Unsatisfactory Proposals

Several suggestions have been put forward that turn out to be rather unsatisfactory. Some propose that Jesus is specifying two births: one must undergo not only natural birth (“born of water”) but also spiritual birth (“born of . . . the Spirit”). People must not only be born, but must be born “again.” There are two primary problems with this interpretation: (1) It is unbearably trite. The first part is saying not much more than that to get into the kingdom, you must exist: you must be born, you must be here. That means all the weight of Jesus’s answer is carried in the second part, “born of . . . the Spirit,” making us wonder what the first part, “born of water,” is contributing to Jesus’s explanation.

(2) I have not been able to find any source in the ancient world that uses “born of water” as a locution to refer to natural birth. It’s not impossible, of course, that the flush of amniotic fluid that precedes natural birth generated the expression “born of water,” but if so, as far as I am aware it has not come to light either in Jewish or Hellenistic sources. On both counts, then, it seems improbable that this is the most likely interpretation.

Others propose what might be called a sacramentarian interpretation: the new birth, they propose, is bound up with both baptism (water) and the Spirit. How in this context Jesus could imagine that Nicodemus could have picked up from the word water an allusion to Christian baptism is not all that clear. Moreover, in the next chapter John draws attention to the fact that Jesus himself didn’t baptize people (John 4:2), but left it to his disciples: there is at least a little self-distancing going on.

Better Explanation

There is a better way of proceeding. First, set out John 3:3 and John 3:5 so that their parallels become obvious:

John 3:3                                                       John 3:5

Very truly I tell you                                        Very truly I tell you

no one can see the kingdom of God            no one can enter the kingdom of God

unless they are born again                           unless they are born of water and the Spirit

Immediately it becomes clear that “born of water and the Spirit” (3:5) is parallel to “born again” (3:5). In other words, “born of water and the Spirit” can’t refer to two births, one natural and one spiritual; rather, it refers to one birth, the birth Jesus is referring to when he speaks of being “born again.” It follows that Jesus’s use of “born of water and the Spirit” is Jesus’s explanation of what he means by “born again,” and is intended to answer Nicodemus’s question.

Second, in what follows it becomes apparent that Jesus thinks his explanation should have been enough for Nicodemus. Indeed, Jesus rebukes Nicodemus for not understanding, even though he is “the teacher of Israel” (3:9–10). As a learned Pharisee, Nicodemus had studied what we would call the Old Testament, along with a great deal of additional theological reflection. From all this learning, what should Nicodemus have picked up from Jesus’s words that should have given him much better understanding of what Jesus was talking about?

That brings us to the third detail, the decisive clue. The question to ask is this: where do “water” and “the Spirit” come together in the Old Testament in a context that promises a new beginning? There are several possibilities, but the most obvious is Ezekiel 36:25–27:

I will sprinkle clean water upon you, and you will be clean. I will cleanse you from all your impurities and from all your idols. I will give you a new heart and put a new spirit in you; I will remove from you your heart of stone and give you a heart of flesh. And I will put my Spirit in you and move you to follow my decrees and be careful to keep my laws.

So God is promising through the prophet Ezekiel, six centuries before Jesus, that a time is coming when there will be a transformative new beginning, characterized by spectacular cleansing symbolized by water that washes away all impurities and idols, and by the powerful gift of the Spirit that transforms the hearts of people. That is what is required if people are to see and enter the kingdom of God.

Small wonder that Jesus repeats, “You must be born again!”

Fourth, with a little more space it would be possible to show how this interpretation of the words “born of water and the Spirit” coheres with the rest of the passage, and indeed with the Gospel of John. Jesus happily insists that this declaration of the need for this kind of new birth has behind it the authority of revelation: he himself has come from heaven to bring it (3:11–13). And the pattern of God reaching down and powerfully saving his people from their sin and idolatry is already there in the Old Testament (3:14–15; cf. Num. 21:4–9).

Indeed, all of this is grounded in the matchless love of God (John 3:16–21), and is accessible to faith: “For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life” (John 3:16).