John 3:9 - Ellicott's Commentary On The Whole Bible

How can these things be? — The answer to the previous question has spoken of a spiritual birth and a spiritual life and a spiritual kingdom, but all this is in a region of which the Rabbinic schools knew nothing. They were the authorised exponents of Law and Prophets; they knew the precise number of words, and the shape of letters; the form of a phylactery, and the width of a fringe; the tithing of garden herbs, and the manner of washing the hands: but spirit, life, a man’s soul born again! — “how can these things be?”