John 3:7 addresses a false teaching in which Nicodemus was no doubt well-schooled: "Do not marvel that I said to you, 'You must be born again.'" The fullness of the word must as used by Christ here is often misunderstood. People think of being born again as a moral duty that they are required to meet, but that was not Jesus' intention. He does not mean that a person must see to it that he becomes born again. No, Jesus says it in terms of being "something that has to happen to you." He intends us to understand that the Father, by an act of His will, must implant His Spirit in an individual's heart for this birth to take place (Romans 9:6-16).
No one can bring about his own human birth; it is the gift of a person's parents. In the same manner, spiritual birth and life are gifts from our Father in heaven. He is sovereign over His creation, and He is engineering the salvation of His Family Kingdom from the birth of each child to his glorification. Did Rebecca's son, Jacob, in any way initiate his calling and receipt of salvation? Yet, though God had chosen him for that while he was still in her womb, Jacob was not actually called and converted until many years after he was born and had produced a life of sinful acts apart from God. Paul explains God's sovereign choice in Romans 9:11-13:
. . . (for the children not yet being born, nor having done any good or evil, that the purpose of God according to election might stand, not of works but of Him who calls), it was said to her, "The older shall serve the younger." As it is written, "Jacob I have loved, but Esau I have hated."
Undoubtedly, Nicodemus, a Pharisee, had been circumcised and therefore had become a party to the Old Covenant in that customary manner. All of his associates—indeed, everyone in the entire Jewish culture—believed essentially the same things regarding salvation. In John 3, however, Jesus is teaching something a great deal different from what Nicodemus had believed all of his adult life. This passage makes it clear that he was having difficulty grasping it. He is being taught that salvation is a gift of God, and God solely and personally initiates it in a circumstance in which the person is essentially passive. God, by means of His Spirit, is entirely sovereign in this matter of producing the spiritual regeneration of which Jesus speaks.