XVII. That Christianity implies a change of nature, is plain from the whole tenor of the gospel.
The Saviour of the world saith, That except a man be born again of water and of the Spirit, he cannot enter into the kingdom of God. We are told, that to as many as received him, to them he gave power to become the Sons of God; which were born not of blood, nor of the will of the flesh, nor of the will of man, but of God.
These words plainly teach us, that Christianity implies an entire change of nature: that as our birth was to us the beginning of a new life, and brought us into a society of earthly enjoyments, so Christianity is another birth, that brings us into a condition as new as when we first saw the light.
We begin again to be, when we enter upon fresh terms of life, have new tempers, new hopes and fears, and an entire change of every thing that can be called good or evil.
This new birth is the very essence and soul of Christianity; it is the seal of the promises, the mark of our sonship, the earnest of our inheritance, and the sure proof of our acceptance with God.
XVIII. If we would know what a change our new life in Christ implies, let us consider what it is to be born of God.
Whosoever is born of God, saith the apostle, doth not commit sin. For his seed remaineth in him: and he cannot sin, because he is born of God. In this the children of God are manifest, and the children of the devil. And again, We know, that whosoever is born of God sinneth not, but he that is begotten of God keepeth himself, and the wicked one toucheth him not. 1 John iii. 10, v. 18.
The same apostle tells us, Whosoever is born of God overcometh the world. He overcometh all worldly desires and worldly fears. He is crucified unto the world and the world crucified unto him. He is dead to the lust of the flesh, the lust of the eye, and the pride of life. And he feareth not them that can kill the body, and after that have nothing more that they can do.
We must therefore examine into the state of our minds, and see whether we are thus changed in our natures, thus born again: whether we are so spiritual, as to have overcome the world: so holy, as that we cannot commit sin; since it is the undeniable doctrine of scripture, that this new birth is as necessary to salvation, as the believing in Jesus Christ.
[♦]XX. There is perhaps no duty more contrary to flesh and blood than the loving our enemies. But this is easy to those that are born of God.