Nicodemus said to Him, “How can a person be born when he is old? He cannot enter his mother’s womb a second time and be born, can he?” Jesus answered, “Truly, truly, I say to you, unless someone is born of water and the Spirit (Note 1), he cannot enter the kingdom of God. That which has been born of the flesh is flesh, and that which has been born of the Spirit is spirit”. John 3:4-6 NASB

To be born again is to enter into a new existence, to have a new mind, a new heart, new views, new principles, new tastes, new affections, new likes, new dislikes, new fears, new joys, new sorrows, new love to things once hated, new hatred to things once loved, new thoughts of God, ourselves, the world, the life to come and salvation. J. C. Ryle (1816 – 1900)

Note 1: In the phrase “born of water and the Spirit,” water is unlikely to refer to Christian baptism as this would have been meaningless to Nicodemus at this point in salvation history. Nor does it mean that baptism is necessary for eternal life since this would contradict the single requirement of faith for eternal life set out elsewhere in John (1:12; 3:16; 3:36; 8:24; 20:31). The better understanding is figurative, as in the woman at the well in John 4:13-14 (“living water that gives eternal life”) or the spiritual cleansing in Ezekiel 36:25 (“I will sprinkle clean water on you”).