That I may not seem as if I would terrify you by letters. That I may not seem, etc. - This is an elliptical sentence, and may be supplied thus: "I have not used this authority; nor will I add any more concerning this part of the subject, lest I should seem, as my adversary has insinuated, to wish to terrify you by my letters.
Related Commentaries of 2 Corinthians 10:9
2 Corinthians 10:9
9 That I may not seem as if I would terrify you by letters.