Jesus informs Nicodemus that he must be gennethe anothen. The first problem is the meaning of anothen: is it “again” or “from above”? The occurrence of this same word in 3:31 with the unquestioned meaning “from above” quickly tilts the evidence in that direction. It also has that meaning in 19:11, 23. (Note that when some [i.e. Ridderbos and Hendriksen] go back to the underlying Aramaic the discussion quickly gets muddied.) So, what does the phrase “born from above” mean in this context? While the expression likely harkens the readers of the FG to think back to 1:12–13 (which it then would mean “born of God”), Jesus himself explains it again to Nicodemus in 3:5: to be born from above means to be born of water and spirit. While water has been interpreted as a reference to baptism, purification, and natural birth, when the background to this verse is seen as Ezek 36:25–27, an explanation becomes easier. The themes in the Ezekiel 36 passage are of cleansing (“sprinkle clean water … and you will be clean”) and a new spirit (“put a new spirit within you”). The result of this action that God will take is that the people will “walk in My statutes” and “observe My ordinances.” The whole passage is a call to repentance, to return to God, and a description of what God will do: “cleans(e) human hearts” and “inner transformation by his Spirit” (so Köstenberger, “John,” 35). In fact, according to Keener, “Qumran’s Manual of Discipline connects Ezek 36 with an immersion in conjunction with repentance (1QS 3.8–9).”
However, Ezekiel 36 is not quoted nor directly alluded to in John 3. Therefore, this (likely) background text should not be pressed too far. Regardless, enough exists in Jesus’ own words to formulate a conclusion: be born from above means to be born of water and spirit. To be born of water refers to being cleansed and being born of the spirit refers to the spirit that God will place in Christians. This “water-spirit” is the origin of the regeneration that is demanded. Both of these result in living a radically different life; they involve changing. Jesus is exhorting Nicodemus to change his life, not just his way of thinking, but all of himself. Hendriksen refers to being born from above as a “radical change,” and Morris as a “divine remaking.” Certainly, Carson’s understanding that this passage’s focus is on “the need for transformation” fits the current understanding as well. This is related to the concept of repentance, whereby someone is called to turn from their sins.