If, however, you bite and devour one another, take care that you are not consumed by one another. Live by the Spirit, I say, and do not gratify the desires of the flesh. For what the flesh desires is opposed to the Spirit, and what the Spirit desires is opposed to the flesh; for these are opposed to each other, to prevent you from doing what you want. But if you are led by the Spirit, you are not subject to the law. (Galatians 5: 15-18)

Here and often elsewhere Paul's letters imply that spirit and flesh are in contention. We understand the ways of the flesh are as bad as the ways of the spirit are good.

This was an important aspect of some Greek thinking. In Judaism both spirit and flesh were more often each seen as God's creations and inherently good.

Above the translator offers, "For what the flesh desires is opposed to the Spirit." Paul's original Greek has a potentially different nuance: "Sarx epithumeo kata pneuma" or the body seeks according to the spirit.

The preposition kata for which the translator uses "opposed" is much more often translated as something less contentious.

Paul also goes on to write, "pneuma kata epithumeo sarx" or the Spirit seeks according to the body.

Above is a detail from a fresco by Michelangelo depicting the conversion of Paul.