From Treatise on Grace, 3 (ca. 1758)
Herein lies the mystery of the vital union that is between Christ and the soul of a believer, which orthodox divines speak so much of. Christ’s love – that is, his Spirit – is actually united to the faculties of their souls. So, it properly lives, acts, and exerts its nature in the exercise of their faculties. By this love being in them, Christ is in them (John 17:26); and so it is said, (1 Cor. 6:17), “But he that is joined to the Lord is one spirit.” And thus it is that the saints are said to live, “yet not they, but Christ lives in them” (Gal. 2:20).
The very promise of spiritual life in their souls is no other than the Spirit of Christ himself. So that they live by his life, as much as the members of the body live by the life of the Lord, and as much as the branches live by the life of the root and stock. “Because I live, you shall live also” (John 14:19). “We are dead: but our life is hidden with Christ in God” (Col. 3:3)…
There is a union with Christ, by the indwelling of the love of Christ, two ways. First, as this is from Christ, and is the very Spirit and life and fulness of Christ; and second, as it acts to Christ. For the very nature of it is love and union of heart to him.
The Spirit of God is a vital principle in the soul, as the breath of life is in the body: (Ezek. 37:5) — “Thus says the Lord God to these bones, I will cause breath to enter into you, and you shall live;” and so verses 9,10… That principle of grace that is in the hearts of the saints is as much a proper communication or participation of the Spirit of God, the third person in the Trinity, as that breath that entered into these bodies is represented to be a participation of the wind that blew upon them.
The prophet says, “Come from the four winds, O breath, and breathe upon these slain that they may live,” is now the very same wind and the same breath; but only was wanted to these bodies to be a vital principle in them, which otherwise would be dead. And, therefore, Christ himself represents the communication of his Spirit to his disciples by his breathing upon them, and communicating to them his breath (John 20:22).
We often, in our common language about things of this nature, speak of a principle of grace. I suppose there is no other principle of grace in the soul than the very Holy Ghost dwelling in the soul and acting there as a vital principle…
If God should take away his Spirit out of the soul – all habits and acts of grace would of themselves cease as immediately as light ceases in a room when a candle is carried out. And no man has a habit of grace dwelling in him any otherwise than as he has the Holy Spirit dwelling in him in his temple, and acting in union with his natural faculties, after the manner of a vital principle.
So that when they act grace, in the language of the apostle, “not they, but Christ living in them.” Indeed, the Spirit of God, united to human faculties, acts very much after the manner of a natural principle or habit. So that one act makes way for another, and so it now settles the soul in a disposition to holy acts; but that it does, so as by grace and covenant, and not from any natural necessity.
Hence the Spirit of God seems in sacred scripture to be spoken of as a quality of the persons in whom it resided. So that they are called spiritual persons; as when we say a virtuous man, we speak of virtue as the quality of the man. It is the Spirit itself that is the only principle of true virtue in the heart. So that to be truly virtuous is the same as to be spiritual.
And thus it is not only with respect to the virtue that is in the hearts of the saints on earth, but also the perfect virtue and holiness of the saints in heaven. It consists altogether in the indwelling and acting of the Spirit of God in their habits. And so, it was with man before the Fall. And so it is with the elect, sinless angels. We have shown that the holiness and happiness of God consist in the Holy Spirit. And so, the holiness and happiness of every holy or truly virtuous creature of God, in heaven or earth, consist in the communion of the same Spirit.
Jonathan Edwards (1703-1758) was a Congregationalist minister and theologian, whose powerful sermons helped to spark the Great Awakening. His Treatise on Grace was published posthumously.