When I therefore was thus minded, did I use lightness? or the things that I purpose, do I purpose according to the flesh, that with me there should be yea yea, and nay nay?
Use lightness - THE levity of which I am accused; namely, by promising more than I performed.
Or ... according to the flesh, that with me there should be yea yea, and nay nay? The "or" expresses a different alternative: Did I act with levity, or (on the other hand) do I purpose what I purpose like fleshly men, so that my "yea must at all costs, even to the disadvantage of others, be yea, and my "nay" nay? (Matthew 14:7; Matthew 14:9.) The repetition, instead of the single "yea" and "nay," hardly agrees with Alford's view, 'What I purpose, do I purpose according to the changeable purposes of the fleshly man, that there may be with me the yea yea, and the nay nay' (i:e., both affirmation and negation concerning the same thing (Matthew 5:37). But James 5:12 proves that the double "yea" here is not equivalent to the single "yea."