Therefore I write these things being absent, lest being present I should use sharpness, according to the power which the Lord hath given me to edification, and not to destruction.
Therefore - because I wish the "sharpness" to be in my letters rather than in deeds.
Edification, and not to destruction - for building up ... not for casting down х kathairesin (G2506)]. To "use sharpness" seems to be casting down rather than building up; therefore he prefers not to have to use it.