When we believe in Jesus Christ all our sins are pardoned; yet the power of sin, although it is weakened and kept under by the dominion of the new-born nature which God infuses into our souls, does not cease, but still lingers in us, and will do so to our dying day. It is a doctrine held by all the orthodox, that there still dwells in the regenerate the lusts of the flesh, and that there still remains 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, has 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 defiles.
For meditation: Are there times when you cannot understand your own behaviour? You are in good company (Romans 7:15-25). But the Christian, having received the new nature, need not and should not give in to the old nature as if he could do nothing about it.