12:1 It is doubtless not profitable for me to boast. I will come to visions and revelations of the Lord: 2 I know a man in Christ who fourteen years ago—whether in the body I do not know, or whether out of the body I do not know, God knows—such a one was caught up to the third heaven. 3 And I know such a man—whether in the body or out of the body I do not know, God knows— 4 how he was caught up into Paradise and heard inexpressible words, which it is not lawful for a man to utter. 5 Of such a one I will boast; yet of myself I will not boast, except in my infirmities. 6 For though I might desire to boast, I will not be a fool; for I will speak the truth. But I refrain, lest anyone should think of me above what he sees me to be or hears from me.
Some feel Paul is speaking of himself in the third person here as the one who went into the third heaven. Others say no. To go down that road really misses the point of what Paul is saying. As for those curious about what the third heaven is, it simply refers to where God dwells. The atmosphere of the earth is the first heaven. Space is the second heaven. God's dwelling place is the third heaven.
Again not really the point either. Paul is talking about boasting. About listing off credentials, accomplishments, gifts, talents, etc... Boasting is done to magnify self. It is done to give a reason why I should be considered better than others. Men have come to or risen up in Corinth boasting of who they are and what they are in order to grab leadership of the church. Right of the top Paul says boasting is not profitable. Then he tells the story of a man who went to heaven either literally or in vision (which we know for sure John did) and says essentially "That is worth boasting about but I will only boast in my infirmities." Then he says "I could speak the truth but I will refrain lest someone thinks more of me than what I am".
I have been invited to speak for special occasions and I hate the part where I am introduced because they try and find whatever they can about you to make you sound as wonderful as possible. Meanwhile I'm sitting there knowing exactly who I am and it's nothing much.
Here's what Paul is trying to say in simple terms. Let your life do the talking. Never be drawn into the game of self-promotion. Never even entertain the thoughts of how you measure up against others. Is a yellow rose superior to a white one? Is a lily superior to an orchid or vice versa?
Jesus said to never seek the best seat at a banquet. Never aspire to the top position. When James and John (with mommy's help) asked if they could sit to His right and left in His kingdom Jesus asked "Are you able to drink the cup?" In His kingdom higher is lower. Leadership is servanthood. Top is bottom. The first will be last. Jesus is King of Kings yet servant of all. The government is on His shoulders. Satan wants His glory and position but wants nothing to do with the part that position plays.
Follow Jesus. Let that journey speak. Add nothing to it. He will place you in the best spot for you, be it higher or lower. He loves you. He is for you. He wants you to blossom and succeed. Leave the boasting to fools and never join their game.