A treatise of original sin ... proving that it is

Lastly, Neither are we to understand this of persons, as if the Apostle meant the carnal man, and the spiritual man, as Isaacl did Isaac, will always oppose one another: For it is clear, he speaketh of two principles within us, the one whereof is flesh, that is, our whole man so far as it is unregenerate, the mind and the will as well as the affections; (for by sin incarnavimus animas nostras, as the Ancient said, our souls are become flesh,) and the whole man so far as he is regenerate: For this in several respects, a godly man is both flesh and Spirit.

Lastly, Neither are we to understand this of persons, as if the Apostle meant the carnal man, and the spiritual man, as Isaacl did Isaac, will alwayes oppose one another: For it is clear, he speaketh of two principles within us, the one whereof is flesh, that is, our whole man so farre as it is unregenerate, the mind and the will as well as the affections; (for by sinne incarnavimus animas nostras, as the Ancient said, our souls are become flesh,) and the whole man so farre as he is regenerate: For this in several respects, a godly man is both flesh and Spirit.

This contrariety in their nature is declared by the effect thereof, They lust one against another: He doth not say, they work one against another, though that be true; but the Apostle would direct us to the head and spring of all outward evil or good, and that is the desire within.

In the next place, the Apostle amplifieth this contrary motion between the flesh and the Spirit from the nature of them; They are [Greek or Hebrew], immediately set one against another, even as darkness and light, as fire and water. Now although it be a Rule, That contraries do expel each other; yet it is also another Rule, That contraries while they are in pugnâ, in fighting with one another, they may be together, as also in remiss degrees: And thus it is with the godly, the flesh and the Spirit are always in conflict; These are the twins in the womb, that by their opposition make the godly mourn, and long for Heaven, where the flesh shall be wholly overcome.