Galatians 5:17 names the conflict precisely: "the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other." The Greek word for "contrary" — antikeitai — means to be set against, to be opposed as adversaries. Paul is not describing two equal forces fighting to a draw. He is describing a genuine, structural opposition that exists inside every believer. The internal conflict is not evidence that you are not a Christian. It is evidence that you are one — because only the person with the Spirit has the Spirit-side of the war.
James 4:1 traces the outer conflicts of life to an inner source: "From whence come wars and fightings among you? come they not hence, even of your lusts that war in your members?" The Greek word for "lusts" — hedonon — is the root of the English word "hedonism." James diagnoses the war within as the engine of the wars without. Peace in relationships often begins with the interior battle being addressed honestly rather than suppressed.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.