One Spirit: The Believer's Union with the Lord

We are not like the angels. Our distinction is not in our works, our intellect, or our devotion, but in this: our spirit is joined to the Lord, who is Himself the Spirit. This union is not a metaphor or a distant hope—it is the very foundation of the Christian life. Through regeneration, God has acted decisively to bring us into an intimacy with Himself that no created being, angelic or otherwise, can claim.

The Two Adams: The Old and the New

Scripture draws a sharp line between the first Adam and the last Adam. The first man, Adam, was made a living soul—he possessed natural life, but that life was limited, earthly, and insufficient for union with God. The last Adam, Christ, is a quickening Spirit. He does not merely restore what was lost; He imparts a new kind of life—spiritual, eternal, and divine.

“And so it is written, The first man Adam was made a living soul; the last Adam was made a quickening spirit."
1 Corinthians 15:45

This is not a minor upgrade. The life of the first Adam leaves us in the realm of the natural, unable to reach God, bound by what is in man. But Christ, as the quickening Spirit, gives us spiritual life. This is the only life that can bring us into union with the Triune God.

Joined to the Lord: One Spirit

This union is not abstract. Paul declares:

“But he that is joined unto the Lord is one spirit."
1 Corinthians 6:17

To be joined to the Lord is to become one spirit with Him. This is the outcome of regeneration—a positive, glorious result. God Himself has accomplished this joining, not by reforming the old man, but by imparting new life from the last Adam. This is not mere improvement; it is a new creation.

The Mutual Indwelling: Christ in You, You in Christ

Jesus, anticipating His resurrection, spoke of a day when this union would be revealed:

“At that day ye shall know that I am in my Father, and ye in me, and I in you."
John 14:20

This is the mystery of mutual indwelling. Because you are joined to the Lord, Christ Himself dwells in you. You are in Him, and He is in you. This is not a mystical experience reserved for the elite; it is the birthright of every regenerated believer. The indwelling of Christ is not a future hope but a present reality, established by God’s own action.

The Insufficiency of the Natural Man

Many in Jesus’ day believed on Him because of the miracles. Yet Scripture is explicit: Jesus did not entrust Himself to them. Why? Because He knew what was in man.

“And needed not that any should testify of man: for he knew what was in man."
John 2:25

Here is the dividing line: mere belief, even in response to miracles, is not enough. The natural man, even when impressed by the supernatural, remains unchanged at the core. Without regeneration, there is no true union with God. Christ does not commit Himself to the old creation. He knows its limits, its corruption, its inability to receive Him.

What Is Lost If This Is Denied?

If you deny or neglect this truth—if you imagine that Christianity is merely about external reform, moral striving, or intellectual assent—you forfeit everything essential. You lose the very foundation of righteousness, sonship, and inheritance. Without union with the Lord, there is no indwelling Christ, no participation in the divine life, no true knowledge of God by faith. To reject this is to remain in Adam, outside the covenant, without hope and without God in the world.

Knowing Christ by Faith—The Only Ground

Through regeneration, you have been brought into union with the Triune God. This is how Christ comes to dwell in you, and it is through your spirit—joined to His—that you know Him by faith. This knowing is not mediated by your senses or your intellect. It is a spiritual knowing, rooted in the finished work of Christ and the new life He imparts.

This is not a secondary doctrine. It is the heart of the gospel. Your union with the Lord is the most profound reality of your existence. It is the dividing line between life and death, between the old creation and the new, between mere religion and true sonship. Do not settle for anything less.