'According to the Flesh' in the Bible

When I therefore was thus determined, did I show fickleness? Or the things that I purpose, do I purpose according to the flesh, that with me there should be the "Yes, yes" and the "No, no?"

Yes, I beg you that I may not, when present, show courage with the confidence with which I intend to be bold against some, who consider us to be walking according to the flesh.

For though we walk in the flesh, we don't wage war according to the flesh;