John 3:9 - Matthew Poole's English Annotations on the Holy Bible

Nicodemus had before spoken as if he thought it a thing impossible, understanding our Saviour of a carnal generation, which he knew could not be repeated: perceiving that he spake of a spiritual birth, he is now posed at the mystery of it; it being a thing the doctrine of which he had not been acquainted with. His carnal stupidity hindered his understanding the first lesson of Christianity, though explained by the Sun of righteousness; and his pride hindered him from confessing his ignorance; he rather judges the doctrine to be absurd and impossible. The like darkness is in every unrenewed mind; regeneration being like that new name, which none understand but those that have it.