2Cor 12:2-4
"I know a man in Christ who fourteen years ago... was caught up to the third heaven. And I know that this man... was caught up into paradise and heard things that cannot be told, which man may not utter."
Paul speaks of himself in the third person. The 'third heaven' / 'paradise' is the immediate presence of God. The experience is ineffable — it cannot be communicated. Paul does not use this to promote himself — he uses it to justify the thorn that came afterward.
2Cor 12:7-10
"So to keep me from becoming conceited because of the surpassing greatness of the revelations, a thorn was given me in the flesh, a messenger of Satan to harass me... And he said to me, ‘My grace is sufficient for you, for my power is made perfect in weakness.’"
The thorn (skolops te sarki) — identity debated (eye disease, epilepsy, human opposition). What matters: it was given to prevent pride, is an instrument of Satan but under God’s control, and God responded not by removing it but by providing sufficient grace. Arkei soi he charis mou — the grace is sufficient.