John 3:6

“That which is born of the flesh, is flesh, etc.] Man by his natural birth, and as he is born according to the flesh of his natural parents, is a mere natural man; that is, he is carnal and corrupt, and cannot discern spiritual things; nor can he, as such, enter into, and inherit the kingdom of God; (see <460214>1 Corinthians 2:14 15:50). And therefore there is a necessity of his being born again, or of the grace of the Spirit, and of his becoming a spiritual man; and if he was to be, or could be born again of the flesh, or ever so many times enter into his mothers womb, and be born, was it possible, he would still be but a natural and a carnal man, and so unfit for the kingdom of God. By…”

“That which is born, &c.--A great universal proposition; "That which is begotten carries within itself the nature of that which begat it" [OLSHAUSEN]. flesh--Not the mere material body, but all that comes into the world by birth, the entire man; yet not humanity simply, but in its corrupted, depraved condition, in complete subjection to the law of the fall (Rom 8:1-9). So that though a man "could enter a second time into his mother's womb and be born," he would be no nearer this "new birth" than before (Job 14:4; Psa 51:5). is spirit--"partakes of and possesses His spiritual nature."”

“That which is born of the flesh - To show the necessity of this change, the Saviour directs the attention of Nicodemus to the natural condition of man. By “that which is born of the flesh” he evidently intends man as he is by nature, in the circumstances of his natural birth. Perhaps, also, he alludes to the question asked by Nicodemus, whether a man could be born when he was old? Jesus tells him that if this could be, it would not answer any valuable purpose; he would still have the same propensities and passions. Another change was therefore indispensable. Is flesh - Partakes of the nature of the parent. Compare Genesis 5:3. As the parents are corrupt and sinful, so will be their…”

“That which is born of the flesh is flesh - Mere flesh, void of the Spirit, yea, at enmity with it; And that which is born of the Spirit is spirit - Is spiritual, heavenly, divine, like its Author. John 3:7”

“born of the flesh: Gen 5:3, Gen 6:5, Gen 6:12; Job 14:4, Job 15:14-16, Job 25:4; Psa 51:10; Rom 7:5, Rom 7:18, Rom 7:25; Rom 8:1, Rom 8:4, Rom 8:5-9, Rom 8:13; Co1 15:47-49; Co2 5:17; Gal 5:16-21, Gal 5:24; Eph 2:3; Col 2:11 that: Eze 11:19, Eze 11:20, Eze 36:26, Eze 36:27; Rom 8:5, Rom 8:9; Co1 6:17; Gal 5:17; Jo1 3:9 John 3:7”