indwelling sin

It is a doctrine, as I believe, taught us in Holy Writ, that when a man is saved by divine grace, he is not wholly cleansed from the corruption of his heart. When we believe in Jesus Christ all our sins are pardoned; yet the power of sin, albeit that it is weakened and kept under by the dominion of the new-born nature which God doth infuse into our souls, doth not cease, but still tarrieth in us, and will do so to our dying day.

It is a doctrine held by all the orthodox, that there dwelleth still in the regenerate, the lusts of the flesh, and that there doth still remain in the hearts of those who are converted by God's mercy, the evil of carnal nature. I have found it very difficult to distinguish, in experimental matters, concerning sin. It is usual with many writers, especially with hymn writers, to confound the two natures of a Christian. Now, I hold that there is in every Christian two natures, as distinct as were the two natures of the God-Man Christ Jesus. There is one nature which cannot sin, because it is born of God—a spiritual nature, coming directly from heaven, as pure and as perfect as God himself, who is the author of it; and there is also in man that ancient nature which, by the fall of Adam, hath become altogether vile, corrupt, sinful, and devilish.

There remains in the heart of the Christian a nature which cannot do that which is right, any more than it could before regeneration, and which is as evil as it was before the new birth—as sinful, as altogether hostile to God's laws, as ever it was—a nature which, as I said before, is curbed and kept under by the new nature in a great measure, but which is not removed and never will be until this tabernacle of our flesh is broken down, and we soar into that land into which there shall never enter anything that defileth. - C.H. Spurgeon from his sermon, Indwelling Sin, June1, 1856