hashicorp/serf — pull request #198 by patrickviet (2014-04-10 14:12:33+00:00)
Title: minor typo in documentation

The word 'therefor' does exist but has a different meaning.
From the context of this sentence I'm guessing that the author really meant to use 'therefore'

http://www.translegal.com/legal-english-lessons/therefore-vs-therefor

TBH I just have fun doing that research.