Human nature in its fourfold state ... In several practical discourses

3. See here, why sin is so pleasant, and religion such a burden to carnal spirits: sin is natural, holiness not so. Oxen cannot feed in the sea, nor fishes in the fruitful fields. A swine brought into a palace, would get away again, to wallow in the mire. A corrupt nature tends ever to impurity.

4. Learn from this, the nature and necessity of regeneration. First, This discovers the nature of regeneration in these two things, (1.) It is not a partial, but a total change, tho' imperfect in this life. Thy whole nature is corrupted, and therefore the cure must go through' every part. Regeneration makes not only a new head for knowledge, but a new heart, and new affections for holiness. All things become new, 2 Cor. v. 17. If one who has received many wounds, should be cured of them all, save one only, he might bleed to death, by that one, as well as a thousand. So if the change go not through the whole man, it is naught. (2.) It is not a change made by human industry, but by the mighty power of the Spirit of God. A man must be born of the Spirit, John iii. 5 Accidental diseases may be cured by men, but these which are natural, not without a miracle, John ix. 22. The change wrought upon men, by good education, or forced upon them, by a natural conscience, tho' it may pass among men for a sav•ing ⟨p. 85⟩change, it is not so; for our nature is corrupt, and none but the God of nature can change it. Tho' a gardiner, ingrafting a pear branch into an apple tree, may make the apple-tree bear pears; yet the art of man cannot change the nature of the apple-tree: so one may pin a new life to his old heart, but he can never change the heart. Secondly, This also shows the necessity of regeneration. It is absolutely necessary in order to salvation,