John 3:4

“Nicodemus saith unto him, etc.] 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 mothers 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.”

“How, &c.--The figure of the new birth, if it had been meant only of Gentile proselytes to the Jewish religion, would have been intelligible enough to Nicodemus, being quite in keeping with the language of that day; but that Jews themselves should need a new birth was to him incomprehensible.”

“How can a man ... - It may seem remarkable that Nicodemus understood the Saviour literally, when the expression “to be born again” was in common use among the Jews to denote a change from “Gentilism” to “Judaism” by becoming a proselyte by baptism. The word with them meant a change from the state of a pagan to that of a Jew. But they never used it as applicable to a Jew, because they supposed that by his birth every Jew was entitled to all the privileges of the people of God. When, therefore, our Saviour used it of a Jew, when he affirmed its necessity of every man, Nicodemus supposed that there was an absurdity in the doctrine, or something that surpassed his comprehension, and he therefore…”

“When he is old - As Nicodemus himself was. John 3:5”

“How: Joh 3:3, Joh 4:11, Joh 4:12, Joh 6:53, Joh 6:60; Co1 1:18, Co1 2:14 John 3:5”