John Chrysostom
Having defended himself in this way, the Apostle then begins to speak much more strongly. The meaning of these words is this: "I lived among you in extreme poverty." This is precisely what "humbling myself" means. "So, do you charge this against me? Do you exalt yourselves over me because I humbled myself among you, begged alms, and endured hardship and hunger, so that I might exalt you?"
How were they exalted when he was in extreme need? They received greater edification and not occasion for scandal. Yet it especially served for their accusation and for the rebuke of their weakness that the Apostle could not lead them to perfection otherwise than by first humbling himself. "So, do you accuse me because I humbled myself? But through this you were exalted."
Since he had said earlier that they slandered him as humble when present in person, but bold when absent, he now defends himself and again strikes them, saying: "I did this for your sake."