John 3:11

"We speak that We do know, and testify that We have seen, and none receiveth Our witness." This He added, making His words credible by another argument, and condescending in His speech to the other's infirmity.

And what is this that He saith, "We speak that We do know, and testify that We have seen"? Because with us the sight is the most trustworthy of the senses, and if we desire to gain a person's belief, we speak thus, that we saw it with our eyes, not that we know it by hearsay; Christ therefore speaks to him rather after the manner of men, gaining belief for His words by this means also. And that this is so, and that He desires to establish nothing else, and refers not to sensual vision, is clear from this; after saying, "That which is born of the flesh is flesh; and that which is born of the Spirit is spirit," He adds, "We speak that we do know, and testify that we have seen." Now this (of the Spirit) was not yet born; how then saith He, "what we have seen"? Is it not plain that He speaks of a knowledge not otherwise than exact?

"And none receiveth our witness." The expression "we know," He uses then either concerning Himself and His Father, or concerning Himself alone; and "no man receiveth," is the expression not of one displeased, but of one who declares a fact: for He said not, "What can be more senseless than you who receive not what is so exactly declared by us?" but displaying all gentleness, both by His works and His words, He uttered nothing like this; mildly and kindly He foretold what should come to pass, so guiding us too to all gentleness, and teaching us when we converse with any and do not persuade them, not to be annoyed or made savage; for it is impossible for one out of temper to accomplish his purpose, he must make him to whom he speaks still more incredulous. Wherefore we must abstain from anger, and make our words in every way credible by avoiding not only wrath, but also loud speaking; for loud speaking is the fuel of passion.

And ye receive not our witness.

As having in Himself the Father and the Spirit Naturally, the Saviour set forth the person of the Witnesses in the plural number, that, as in the law of Moses, by the mouth of two or three witnesses, what is said may be established. For He shows that the Jews in no wise will to be saved, but with unbridled and heedless impetus are they being borne unto the deep pit of perdition. For if they can neither from their great unlearning understand what is proclaimed to them, nor yet receive it in faith, what other means of salvation may be devised for them? Well then and very justly did the Saviour say that Jerusalem would be without excuse, as snatching upon herself self-called destruction. O Jerusalem, Jerusalem, saith He, that killest the prophets and stonest them, which are sent unto thee, how often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not! Behold your house is left unto you.

Verily, verily, I say unto thee, We speak that we do know and testify that we have seen.

He finds the man careless of learning and exceedingly uninstructed and, by reason of his great grossness of mind, utterly unable to be led unto the comprehension of Divine doctrines, albeit many words had been expended with manifold examples. Whence letting alone, as was fitting, accurate explanation, He at length advises him to accept in simple faith, what he cannot understand. He testifies that Himself knows clearly what He saith, by the illustriousness of His Person showing that yet to gainsay is most dangerous. For it was not likely that Nicodemus would forget, who had affirmed that he knew it of our Saviour Christ, that He was a Teacher come from God. But to resist one who is from God and God, how would it not be fraught with peril? for the thing is clearly a fighting with God. But hence we ought to know, who have authority to teach, that for those just come to the faith, faith in simple arguments is better than any deep reasoning, and more elaborate explanation. And Paul also used to feed with milk some, not yet able to bear stronger meats. And the most wise Solomon again somewhere says to us, Thou shalt wisely know the souls of thy flock, meaning that we should not set before those who come to us the word of doctrine indiscriminately, but fitly adapted to the measure of each.

He advises Nicodemus to accept in simple faith what he cannot understand. Jesus testifies that he himself knows clearly what he says because of who he is, and to doubt what he says is a very dangerous thing. For it was not likely that Nicodemus would forget that he had earlier affirmed that our Savior Christ was a “teacher who had come from God.” But to resist one who is both from God, and God, is terribly fraught with peril since one is clearly fighting with God. That is why we, who have the authority to teach, should rather provide simple arguments for those who have just come to faith, rather than the more elaborate explanations … not applying doctrine indiscriminately but appropriately adapted to what each can handle.

Since he has the Father and the Spirit naturally, the Savior set forth the person of the witnesses in the plural number so that, as in the law of Moses, by the mouth of two or three witness what is said may be established.

Or, the plural number may have this meaning; I, and they who are born again of the Spirit, alone understand what we speak; and having seen the Father in secret, this we testify openly to the world; and ye, who are carnal and proud, receive not our testimony.

(Hom. in Oct. Pent.) Why, it is asked, does He speak in the plural number, We speak that we do know? Because the speaker being the Only-Begotten Son of God, He would show that the Father was in the Son, and the Son in the Father, and the Holy Ghost from both, proceeding indivisibly.

This is not said of Nicodemus, but of the Jewish race, who to the very last persisted in unbelief.

"Moreover, I speak of what I know and what I have seen, that is, I know with precision." For by the word "have seen" He indicates not bodily sight, but the most precise knowledge.
"But you do not accept Our testimony, that is, Mine." The Lord says this not to Nicodemus alone, but extends it to the entire race of the Jews, who to the end remained in unbelief.

Secondly, he rebukes him for his slowness on account of the character of the person who is speaking. For it is tolerable if one does not acquiesce to the statements of an ignorant person; but it is reprehensible to reject the statements of a man who is wise and who possesses great authority. And so he says, Amen, amen I say to you, that we know of what we speak, and we bear witness of what we see. For a qualified witness must base his testimony on hearing or sight: "What we have seen and heard" (1 Jn 1:3). And so the Lord mentions both: we know of what we speak, and we bear witness of what we see. Indeed, the Lord as man knows all things: "Lord, you know all things" (below 21:17); "The Lord, whose knowledge is holy, knows clearly" (2 Mc 6:30). Further, he sees all things by his divine knowledge: "I speak of what I have seen with my Father," as we read below (8:38).

He speaks in the plural, we know, we see, in order to suggest the mystery of the Trinity: "The Father, who dwells in me, he does the works" (below 14:10). Or, we know, i.e., I, and others who have been made spiritual, because "No one knows the Father but the Son, and he to whom the Son wishes to reveal him" (Mt 11:27).

But you do not accept our testimony, so approved, so solid. "And his testimony no one accepts" (below 3:32).