Jesus answered, "Most assuredly I tell you, unless one is born of water and spirit, he can't enter into the Kingdom of God!
We must always keep in remembrance the design of Christ, which we have already explained; namely, that he intended to exhort Nicodemus to newness of life, because he was not capable of receiving the Gospel, until he began to be a new man. It is, therefore, a simple statement, that we must be born again, in order that we may be the children of God, and that the Holy Spirit is the Author of this second birth. For while Nicodemus was dreaming of the regeneration (παλιγγενεσία) or transmigration taught by Pythagoras, who imagined that souls, after the death of their bodies, passed into other bodies, (58) Christ, in order to cure him of this error, added, by way of explanation, that it is not in a natural way that men are born a second time, and that it is not necessary for them to be clothed with a new body, but that they are born when they are renewed in mind and heart by the grace of the Spirit. 