Therefore I write these things ... - This is a kind of apology for what he had said, and especially for the apparently harsh language which he had felt himself constrained to use. He had reproved them; he had admonished them of their faults; he had threatened punishment, all of which was designed to prevent the necessity of severe measures when he should be with them.
Lest being present I should use sharpness - In order that when I come I may not have occasion to employ severity; see the sentiment explained in the note on 2 Corinthians 10:2.
According to the power ... - That I may not use the power with which Christ has invested me for maintaining discipline in his church. The same form of expression is found in 2 Corinthians 10:8; see the note on that place.