Ferguson reminds us that “union with Christ by the Spirit is grounded in his union with us in our humanity.” In other words, Jesus became flesh in order to become the firstborn of a saved humanity. Therefore, the Spirit’s work of uniting us to Christ is equally a work of returning and restoring to us full humanity.

A Sunday school class has given me opportunity to revisit Sinclair Ferguson’s masterful work The Holy Spirit. In the fifth chapter, Dr. Ferguson argues convincingly that understanding salvation through the lens of our union with Christ is a much more satisfying method than the ordo salutis–this argument is made primarily by noting how ordo salutis examines the relationship between the various aspects of our salvation (like effectual calling, justification and sanctification) while union with Christ examines each of those same aspects in a much more Christ-centered way. And in the context of a book about the Holy Spirit, he argues that “The central role of the Spirit is to reveal Christ and to unite us to him and to all those who participate in his body.”

The great encouragement of the chapter comes at the end considers the implications of the Spirit’s great work of uniting us to Christ and the centrality of Jesus to every aspect of our salvation.

First, Ferguson quotes John Calvin, challenging us to honor the Spirit’s work by finding everything we need in Jesus Christ:

We see that our salvation and all its parts are comprehended in Christ. We should therefore take care not to derive the least portion of it from anywhere else. If we seek salvation, we are taught by the very name of Jesus that it is ‘of him’ (1 Cor. 1:30). If we seek any other gifts of the Spirit, they will be found in his anointing. If we seek strength, it lies in his dominion; if purity, in his conception; if gentleness, it appears in his birth…If we seek redemption, it lies in his passion; if acquittal, in his condemnation; if remission of the curse, in his cross (Gal. 3:13); if satisfaction, in his sacrifice; if purification, in his blood; if reconciliation, in his descent into hell; if mortification of the flesh, in his tomb; if newness of life, in his resurrection…In short, since rich store of every kind of good abounds in him, let us drink our fill from this fountain and from no other.

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