John Gill Commentary 2 Corinthians 12:5

"On behalf of such a one will I glory: but on mine own behalf I will not glory, save in [my] weaknesses." — 2 Corinthians 12:5 (ASV)

Of such an one will I glory
The apostle in great modesty seems to speak of some other person, and not himself, as caught up into the third heaven, when he yet means himself; and does as it were distinguish himself from himself; himself in paradise from himself on earth; his sense is, that though he might lawfully glory of such a person so highly exalted and favoured, yet since this was his own case, he chose to forbear, and say no more of it:

yet of myself I will not glory ;
though he could, and might, and did glory in the Lord, who had done such great things for him; as that he was in Christ, and knew himself to be so, had been rapt up into heaven, and heard things unutterable; yet he would not glory of these things as from himself, as owing to any merit or worthiness of his, but as instances of mere favour, grace, and goodness; if he gloried of anything of himself in his present state and condition, it should be of his weaknesses:

but in mine infirmities ;
not his sinful ones, for these he mourned over, and was humbled before God and man under a sense of; but his many pressing difficulties of life, heavy reproaches, very great afflictions, and violent persecutions he endured for Christ's sake; see (2 Corinthians 12:10) .