What does John 3:8 mean?
Jesus is using a very clever play on words here. In English, this is almost entirely lost. This and a prior verse (John 3:6) use the Greek word pneuma, which can be translated several different ways. It can mean "spirit," lowercase, or "Spirit," capitalized, or "wind," depending on the context. All of these have a religious meaning which Nicodemus would have recognized. Wind—or breath—is often symbolic of the Holy Spirit (Job 33:4; John 20:22; Acts 2:2). The term would also have reminded Nicodemus of Ezekiel 37:1–14. In that passage, the wind blows across dry bones and brings them back to life.In verse 7, Jesus explained that the need for rebirth should not surprise Nicodemus. "Flesh" and Spirit" are opposed to each other, so the only way for a person to take on a new nature is by being "born again." The exact reasons why this happens, and how it happens, will always be a mystery to us. We can't really see the wind or predict everything about it. In the same way, the work of the Spirit isn't something we can completely understand. We know that what the Spirit does works, and why, but the intricacies are beyond our comprehension.