In the flesh (en sarki). But that is a very different thing from walking kata sarka according to the standards of the flesh as his enemies charged. It is easy enough to make insinuations.
We war (strateuometha). Literary plural again after logizomai in 2Co 10:2. Old word to lead an army (stratos). In N.T. only in the middle as here. Paul admits that he fights, but only the devil and his agents even if wearing the livery of heaven. Paul knew the Roman army well. He knows how to use the military metaphor.