Jamieson, Fausset and Brown on 2 Corinthians 1:17

17. use lightness--Was I guilty of levity? namely, by promising more than I performed.

or ... according to the flesh, that with me there should be yea, yea ... 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 worldly (fleshly) men, so that my "yea" must at all costs be yea, and my "nay" nay [Bengel, Winer, Calvin], (Mt 14:7, 9)? The repetition of the "yea" and "nay" hardly agrees with Alford's view, "What I purpose do I purpose according to the changeable purposes of the fleshly (worldly) man, that there may be with me the yea yea, and the nay nay (that is, both affirmation and negation concerning the same thing)?" The repetition will thus stand for the single yea and nay, as in Mt 5:37; Jas 5:12. But the latter passage implies that the double "yea" here is not equivalent to the single "yea": Bengel's view, therefore, seems preferable.