Jesus answered, "Most assuredly I tell you, unless one is born of water and spirit, he can't enter into the Kingdom of God!
Some commentators take the "water" as an allusion to water baptism and the "spirit" as referring to the Holy Spirit. [Note: E.g., R. E. Brown, The Gospel According to John: Introduction, Translation and Notes, 2:139-141.] According to this view spiritual birth happens only when a person undergoes water baptism and experiences regeneration by the Holy Spirit. Some advocates of this view see support for it in the previous reference to water baptism (John 1:26; John 1:33). However, Scripture is very clear that water baptism is a testimony to salvation, not a prerequisite for it (cf. John 3:16; John 3:36; Ephesians 2:8-9; Titus 3:5). In addition, this meaning would have had no significance for Nicodemus. He knew nothing of Christian baptism. Furthermore Jesus never mentioned water baptism again in clarifying the new birth to Nicodemus.