Two principles in every believer
Indeed, this great point runs through all the epistles of Saint Paul, yes, through all the holy scriptures. There are two contrary principles in believers, nature and grace, the flesh and the Spirit. Almost all the directions and exhortations in scripture rest on this supposition. They point at wrong tempers or practices in people whom the inspired writers nevertheless acknowledge to be believers. And those believers are continually urged to fight with these things, and to conquer them, by the power of the faith which was in them.
1771 text
3. Indeed this grand point, that there are two contrary principles in believers, nature and grace, the flesh and the Spirit, runs through all the epistles of St. Paul, yea through all the holy scriptures: almost all the directions and exhortations therein, are founded on this supposition: pointing at wrong tempers or practices in those, who are notwithstanding acknowledged by the inspired writers to be believers. And they are continually exhorted to fight with and conquer these, by the power of the faith which was in them.