Albert Barnes Commentary 2 Corinthians 13:10

"For this cause I write these things while absent, that I may not when present deal sharply, according to the authority which the Lord gave me for building up, and not for casting down." — 2 Corinthians 13:10 (ASV)

Therefore I write these things, etc. 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 would be with them.

Lest being present I should use sharpness. In order that when I come, I may not have to use severity. See the sentiment explained in the notes on 2 Corinthians 10:2.

According to the power, etc. 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 notes on that verse).