“I must go on boasting. Though there is nothing to be gained by it, I will go on to visions and revelations of the Lord.” vs1

There's nothing to be gained by Paul boasting. He doesn't walk around puffed up, bragging about himself. He was brought to boast for the good of others. Now, he'll speak about visions and revelations, but everything is to magnify Christ. It's a matter of the heart, and it's so sweet to be around people where all glory goes to Christ: it's nothing of self, and all is for the good of others. This is Christian friendship and community, where Christ is all. He's experienced and loved.

“I know a man in Christ who fourteen years ago was caught up to the third heaven—whether in the body or out of the body I do not know, God knows.” vs2

This is an important doctrine. In all things, God knows, and we rest in Him. In trials, disappointments, and slander. In weakness, burden, and needs, God knows. In doctrine and in the future, God knows. Paul says, "I don’t know if I was in the body or not. I leave it in God's hands." Leave a million things there!

God knows, and He loves us, forgives us, and justifies us. God knows, and He will help. He has all power. We don't have to know. Nobody else must know. God knows, and He is our Friend!

"he heard things that cannot be told, which man may not utter"

There are things that we can't put into words. Paul saw things he can't communicate. It's not in the realm yet revealed! There are mysteries and beauties, unseen ecstasies and pleasures, so that a man is foolish to give it all up. Things are MORE GLORIOUS than they appear. Our union with Christ in His love is greater than comprehension. Our security and His reward are so great, as is the paradise of God. Enter in one step: It's the place of all perfection, amazement, and joy. It's mind boggling and thrilling; it's beyond comprehension.

Oh, how rich is our reward! Hang on a little while longer. Hold on to it in hope. Don't fear the next world; it is gain.

On behalf of this man I will boast, but on my own behalf I will not boast, except of my weaknesses—” vs5

Paul will only boast of his weaknesses, so that the power of Christ may be known. He wants all glory to be His! This marks a spiritual man: he's continually pointing to Christ, setting the captives free. He's drawn to Him like a moth to the light. He loves Him, and sees all worthiness and completeness in Him. He has NO OTHER knowledge, wisdom, or sanctification. In Christ is the fullness of God bodily! We are circumcised in Him, buried in Him, and Risen, even when we were dead in trespasses and sins. Our salvation was completely outside of ourselves, in Him, and given before time began.

"Hallelujah" is the spiritual man's praise, as he ponders Christ: he wants everyone to see Him and know Him [1 Cor 2:2]. He has no tricks or extra knowledge! He has Christ, and he gives Him to people.