2 I knew a man in Christ above fourteen years ago, (whether in the body, I cannot tell; or whether out of the body, I cannot tell: God knoweth;) such an one caught up to the third heaven.
[AD 202] Irenaeus on 2 Corinthians 12:2
For that there are spiritual creatures in the heavens, all the Scriptures loudly proclaim; and Paul expressly testifies that there are spiritual things when he declares that he was caught up into the third heaven,

[AD 220] Tertullian on 2 Corinthians 12:2
It, too, has eyes and ears of its own, by means of which Paul must have heard and seen the Lord; it has, moreover all the other members of the body by the help of which it effects all processes of thinking and all activity in dreams.

[AD 235] Hippolytus of Rome on 2 Corinthians 12:2
Paul the apostle, he says, knew of this gate, partially opening it in a mystery, and stating "that he was caught up by an angel, and ascended as far as the second and third heaven into paradise itself; and that he beheld sights and heard unspeakable words which it would not be possible for man to declare."

[AD 311] Methodius of Olympus on 2 Corinthians 12:2
For the apostle, he says, does not suppose paradise to be in the third heaven, in the opinion of those who knew how to observe the niceties of language, when he says, "I know such a man caught up to the third heaven; and I know such a man, whether in the body or out of the body, God knoweth, that was caught up into paradise."

[AD 384] Ambrosiaster on 2 Corinthians 12:2
Paul mentions both things because either is possible. It may seem to someone that it is nothing much to be caught up into the third heaven, since that is where the moon is, but that is not right. What this means is that he was caught up beyond all the stars of the universe into the heaven which is third in the hierarchy of spiritual heavens.

[AD 390] Gregory of Nazianzus on 2 Corinthians 12:2
Had Paul been able to express the experiences gained from the third heaven and his progress, ascent or assumption to it, we should perhaps have known more about God—if this really was the secret meaning of his rapture. But since they were ineffable, let them have the tribute of our silence. Let us give this much attention to Paul when he says: “We know in part and we prophesy in part.” This and the like is the confession of one who is no mere layman in knowledge, of one who threatens to give proof of Christ speaking in him, of a great champion and teacher of truth.

[AD 407] John Chrysostom on 2 Corinthians 12:2-5
"I knew a man, fourteen years ago (whether in the body, I know not; or out of the body, I know not: God knows;) such an one caught up even to the third heaven. And I know how that he was caught up into Paradise, (whether in the body, I know not; or out of the body, I know not;) and heard unspeakable words, which it is not lawful for a man to utter. On behalf of such an one will I glory: but on my own behalf I will not glory."

Great indeed was this revelation. But this was not the only one: there were many others besides, but he mentions one out of many. For that there were many, hear what he says: "Lest I should be exalted overmuch through the exceeding greatness of the revelations." 'And yet,' a man may say, 'if he wished to conceal them, he ought not to have given any intimation whatever or said anything of the sort; but if he wished to speak of them, to speak plainly.' Wherefore then is it that he neither spoke plainly nor kept silence? To show by this also that he resorts to the thing unwillingly. And therefore also he has stated the time, "fourteen years." For he does not mention it without an object, but to show that he who had refrained for so long a time would not now have spoken out, except the necessity for doing so had been great. But he would have still kept silence, had he not seen the brethren perishing. Now if Paul from the very beginning was such an one as to be counted worthy of such a revelation, when as yet he had not wrought such good works; consider what he must have grown to in fourteen years. And observe how even in this very matter he shows modesty, by his saying some things, but confessing that of others he is ignorant. For that he was caught up indeed, he declared, but whether "in the body" or "out of the body" he says he does not know. And yet it would have been quite enough, if he had told of his being caught up and had been silent [about the other]; but as it is, in his modesty he adds this also. What then? Was it the mind that was caught up and the soul, while the body remained dead? Or was the body caught up? It is impossible to tell. For if Paul who was caught up and whom things unspeakable, so many and so great, had befallen was in ignorance, much more we. For, indeed, that he was in Paradise he knew, and that he was in the third heaven he was not ignorant, but the manner he knew not clearly. And see from yet another consideration how free he is from pride. For in his narrative about "the city of the Damascenes" [2 Corinthians 11:32] he confirms what he says, but here not; for it was not his aim to establish this fact strongly, but to mention and intimate it only. Wherefore also he goes on to say, "Of such an one will I glory;" not meaning that he who was caught up was some other person, but he so frames his language in the best manner he possibly could, so as at once to mention the fact, and to avoid speaking of himself openly. For what sequence would there be in bringing some one else forward, when discoursing about himself? Wherefore then did he so put it? It was not all one to say, 'I was caught up,' and, "I knew one that was caught up;" and 'I will glory of myself,' and, "I will glory of such an one." Now if any should say, 'And how is it possible to be caught up without a body?' I will ask him, 'How is it possible to be caught up with a body?' for this is even more inexplicable than the other, if you examine by reasonings and do not give place to faith.

But wherefore was he also caught up? As I think, that he might not seem to be inferior to the rest of the Apostles. For since they had companied with Christ, but Paul had not: He therefore caught up unto glory him also. "Into Paradise." For great was the name of this place, and it was everywhere celebrated. Wherefore also Christ said, "Today you shall be with Me in Paradise." [Luke 23:43]

"On behalf of such an one will I glory?" wherefore? For if another were caught up, wherefore do you glory? Whence it is evident that he said these things of himself. And if he added, "but of myself I will not glory," he says nothing else than this, that, 'when there is no necessity, I will say nothing of that kind fruitlessly and at random;' or else he is again throwing obscurity over what he had said, as best he might. For that the whole discourse was about himself, what follows also clearly shows; for he went on to say...

[AD 407] John Chrysostom on 2 Corinthians 12:2
Paul specifies that it was fourteen years before in order to show that he would not normally have spoken about it at all had he not been provoked. And even then, notice that there are some things he is still ignorant about. He knows that he was in paradise, but whether he was in the body or not he cannot tell. Why did this happen to him? I think it was probably so that he would not feel inferior to the other apostles, who had all been with Christ while he was on earth.

[AD 418] Pelagius on 2 Corinthians 12:2
You see how pressed Paul was to make his point, if he had to recall something which had happened as long as fourteen years before.