The Apostle Paul
2 Corinthians 12:21BSB·traditional attribution

I am afraid that when I come again, my God will humble me before you, and I will be grieved over many who have sinned earlier and have not repented of their acts of impurity, sexual immorality, and debauchery.

John Calvin Reformed @genevareformer

21. Lest, when I come, my God should humble me His abasement was reckoned to him as a fault. The blame of it he throws back upon the Corinthians, who, when they should have honored his Apostleship, loaded it, on the contrary, with disgrace; for their proficiency “Qu’ils eussent proufite en sainctete de vie;” — “That they had made progress in holiness of life.” would...

Matthew Henry Presbyterian @wholebiblehenry

In these verses the apostle addresses himself to the Corinthians two ways: - I. He blames them for what was faulty in them; namely, that they had not stood up in his defence as they ought to have done, and so made it the more needful for him to insist so much on his own vindication.

Commenting on 2 Corinthians 12:11-21

Albert Barnes Presbyterian @notesbybarnes

Verse 21. And lest, when I come again, my God will humble me, etc. Lest I should, be compelled to inflict punishment on those whom I supposed to have been converted under my ministry. I had rejoiced in them as true converts. I had counted them as among the fruit of my ministry.