John Gill Commentary John 3:4

"Nicodemus saith unto him, How can a man be born when he is old? can he enter a second time into his mother`s womb, and be born?" — John 3:4 (ASV)

Nicodemus says to him
Understanding him of a natural birth, to be repeated:

how can a man be born when he is old ?
as it seems by this, he himself now was:

can he enter the second time into his mother's womb, and be born ?
the Ethiopic version adds, "again"; and the Arabic version, "and then be born"; this he urges, as absurd, impracticable, and impossible; and which shows him to have been as yet a natural man, who could not receive nor discern spiritual things.