2 The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him.
[AD 220] Tertullian on John 3:2
In like manner John says: "And it doth not yet appear what we shall be: we know, however, that when He shall be manifest, we shall be like Him." We are far indeed from being already what we know not of; we should, of course, be sure to know it if we were already (like Him).

[AD 407] John Chrysostom on John 3:1-3
(Hom. xxiv. 1) As yet however he was withheld by Jewish infirmity: and therefore he came in the night, being afraid to come in the day. Of such the Evangelist speaks elsewhere, Nevertheless, among the chief rulers also many believed on Him; but because of the Pharisees they did not confess Him, lest they should be put out of the synagogue. (John 12:42)

(Hom. xxiv. 2. in Joan) He did not however conceive any great idea of them from His miracles; and attributed to Him as yet only a human character, speaking of Him as a Prophet, sent to execute a commission, and standing in need of assistance to do His work; whereas the Father had begotten Him perfect, selfsufficient, and free from all defect. It being Christ's design however for the present not so much to reveal His dignity, as to prove that He did nothing contrary to the Father; in words He is often humble, while His acts ever testify His power. And therefore to Nicodemus on this occasion He says nothing expressly to magnify Himself; but He imperceptibly corrects his low views of Him, and teaches him that He was Himself all-sufficient, and independent in His miraculous works. Hence He answers, Verily, verily, I say unto you, Except a man be born again, he cannot see the kingdom of God.

(Hom. xxiv. 2) He says therefore, Except a man be born again, he cannot see the kingdom of God: as if He said, Thou art not yet born again, i. e. of God, by a spiritual begetting; and therefore thy knowledge of Me is not spiritual, but carnal and human. But I say unto thee, that neither thou, nor any one, except he be born again of God, shall be able to see the glory which is around me, but shall be out of the kingdom: for it is the begetting by baptism, which enlightens the mind. Or the meaning is, Except thou art born from above, and hast received the certainty of my doctrines, thou wanderest out of the way, and art far from the kingdom of heaven. By which words our Lord discloses His nature, showing that He is more than what He appears to the outward eye. The expression, From abovea, means, according to some, from heaven, according to others, from the beginning. Had the Jews heard it, they would have left Him in scorn; but Nicodemus shows the love of a disciple, by staying to ask more questions.

[AD 407] John Chrysostom on John 3:2
Nicodemus yet lingers below, has yet human thoughts concerning Him, and speaks of Him as of a Prophet, imagining nothing great from His miracles. "We know," he says, "that Thou art a Teacher come from God." "Why then comest thou by night and secretly, to Him that speaketh the things of God, to Him who cometh from God? Why conversest thou not with Him openly?" But Jesus said nothing like this to him, nor did He rebuke him; for, saith the Prophet, "A bruised reed shall He not break, and smoking flax shall he not quench; He shall not strive nor cry": and again He saith Himself, "I came not to condemn the world, but to save the world."

"No man can do these miracles, except God be with him." Still here Nicodemus speaks like the heretics, in saying, that He hath a power working within Him, and hath need of the aid of others to do as He did. What then saith Christ? Observe His exceeding condescension. He refrained for a while from saying, "I need not the help of others, but do all things with power, for I am the Very Son of God, and have the same power as My Father," because this would have been too hard for His hearer; for I say now what I am always saying, that what Christ desired was, not so much for a while to reveal His own Dignity, as to persuade men that He did nothing contrary to His Father.

[AD 407] John Chrysostom on John 3:2-3
Nicodemus saith, "Rabbi, we know that Thou art a Teacher come from God, for no man can do the miracles that Thou doest, except God be with him." He thought he had said something great when he had spoken thus of Christ. What then saith Christ? To show that he had not yet set foot even on the threshold of right knowledge, nor stood in the porch, but was yet wandering somewhere without the palace, both he and whoever else should say the like, and that he had not so much as glanced towards true knowledge when he held such an opinion of the Only-Begotten, what saith He?

"Verily, verily, I say unto thee, Except a man be born again, he cannot see the Kingdom of God."

That is, "Unless thou art born again and receivest the right doctrines, thou art wandering somewhere without, and art far from the Kingdom of heaven." But He does not speak so plainly as this. In order to make the saying less hard to bear, He does not plainly direct it at him, but speaks indefinitely, "Except a man be born again": all but saying, "both thou and any other, who may have such opinions concerning Me, art somewhere outside the Kingdom."

[AD 407] John Chrysostom on John 3:1-2
This man appears also in the middle of the Gospel, making defense for Christ; for he saith, "Our law judgeth no man before it hear him"; and the Jews in anger replied to him, "Search and look, for out of Galilee ariseth no prophet." Again after the crucifixion he bestowed great care upon the burial of the Lord's body: "There came also," saith the Evangelist, "Nicodemus, which came to the Lord by night, and brought a mixture of myrrh and aloes, about an hundred pound weight." And even now he was disposed towards Christ, but not as he ought, nor with proper sentiments respecting Him, for he was as yet entangled in Jewish infirmity. Wherefore he came by night, because he feared to do so by day. Yet not for this did the merciful God reject or rebuke him, or deprive him of His instruction, but even with much kindness conversed with him and disclosed to him very exalted doctrines enigmatically indeed, but nevertheless He disclosed them. For far more deserving of pardon was he than those who acted thus through wickedness.

[AD 430] Augustine of Hippo on John 3:1-2
(Tr. xi) He had said above that, when He was at Jerusalem—many believed in His Name, when they saw the miracles which He did. Of this number was Nicodemus, of whom we are told; There was a man of the Pharisees, Nicodemus, a ruler of the Jews.

(Tr. xi. c. 3, 4) Nicodemus was one of the number who believed, but were not as yet born again. Wherefore he came to Jesus by night. Whereas those who are born of water and the Holy Ghost, are addressed by the Apostle, Ye were sometimes darkness, but now are ye light in the Lord. (Eph. 5:8)

(Tr. xi. c. 3) What the ground of his belief was, is plain from what immediately follows: For no one can do these miracles that Thou doest, except God be with him. Nicodemus then was one of the many who believed in His Name, when they saw the signs that He did.

(Tr. xi. c. 4) Those then are the persons to whom Jesus commits Himself, those born again, who come not in the night to Jesus, as Nicodemus did. Such persons immediately make professsion.

[AD 430] Augustine of Hippo on John 3:1-2
Therefore, since Nicodemus was of that number, he came to the Lord, but came by night; and this perhaps pertains to the matter. Came to the Lord, and came by night; came to the Light, and came in the darkness. But what do they that are born again of water and of the Spirit hear from the apostle? "Ye were once darkness, but now light in the Lord; walk as children of light"; and again, "But we who are of the day, let us be sober." Therefore they who are born again were of the night, and are of the day; were darkness, and are light. Now Jesus trusts Himself to them, and they come to Jesus, not by night, like Nicodemus; not in darkness do they seek the day. For such now also profess: Jesus has come near to them, has made salvation in them; for He said, "Except a man eat my flesh, and drink my blood, he shall not have life in him."

[AD 444] Cyril of Alexandria on John 3:2
More ready is Nicodemus to believe, but overcome by no good fear, and not despising the opinion of men, he refuses boldness, and is divided in opinion into two, and halts in purpose, feeble upon both his knee joints, as it is written, forced by the convictions of his conscience to the duty of believing by reason of the exceedingness of the miracles, but esteeming the loss of rulership over his own nation a thing not to be borne, for he was a ruler of the Jews. Deeming that he can both preserve his repute with them, and be a disciple secretly, he cometh to Jesus, making the darkness of the night an aider of his scheme, and by his secret coming convicted of double mindedness.

[AD 444] Cyril of Alexandria on John 3:2
Nicodemus imagines that he can become pious enough to attain salvation merely by marveling at the wonders Jesus had done.… Calling Jesus a teacher from God and a co-worker with him, he does not yet know that Jesus is by nature God, nor does Nicodemus understand the plan of salvation according to the flesh. Instead, he still approaches Jesus as a mere man and has only a slight conception of who he is.

[AD 735] Bede on John 3:2
This ruler of the Jews came to Jesus by night, hoping, that is, by so secret an interview, to learn more of the mysteries of the faith; the late public miracles having given him a rudimentary knowledge of them.

[AD 735] Bede on John 3:1-2
His rank is given, A ruler of the Jews; and then what he did, This man came to Jesus by night: hoping, that is, by so secret an interview, to learn more of the mysteries of the faith; the late public miracles having given him an elementary knowledge of them.

[AD 853] Haymo of Halberstadt on John 3:2
(Hom. in Oct. Pent.) Or, well may it be said that he came in the night, enveloped, as he was, in the darkness of ignorance, and not yet come to the light, i. e. the belief that our Lord was very God. Night in the language of Holy Writ is put for ignorance. And said unto him, Rabbi, we know that Thou art a teacher come from God. The Hebrew Rabbi, has the meaning of Magister in Latin. He calls him, we see, a Master, but not God: he does not hint at that; he believes Him to be sent from God, but does not see that He is God.