Richard Sibbes, my favorite English puritan (1577-1635), treated human salvation very much as Martin Luther had done in Saxony a century before—mainly as a function of ontology. It shifted the focus away from the more judicial notion of salvation common in his day.
In the judicial view Jesus took up the Father’s judgment against sin—death—on behalf of the elect. It was a legal exchange aligned with the Old Testament sacrificial model, with Jesus offering his own blood in place of the blood of bulls and goats.
To be clear, the Bible clearly presents Jesus as a “better sacrifice”—as we read, for instance, in Hebrews chapter nine—but if the truth of Christ’s atoning death is left to stand by itself we don’t gain the full picture of God’s ambition in creation and redemption.
Luther’s best-known summary of the ontology of salvation is offered in his “On the Freedom of a Christian.” Here’s the key item: “The third incomparable grace of faith is this, that it unites the soul to Christ, as the wife to the husband.” Marriage, he taught, brings salvation through the exchange of moral good and evil in marital union: Jesus takes his bride’s sin and she receives his righteousness.
Sibbes was likely aware of this from his reading of Luther. Yet the bigger issue is that both men relied on the Bible for the same imagery. Sibbes wrote of marital union—in just one of many sermons on the subject—in his series, “The Fountain Opened, or The Mystery of Godliness Revealed.” The sermons, in Sibbes’ Works, v.5, 457-540, were linked to 1 Timothy 3:16. Let me cite Sibbes at length and then comment.
“There are three unions:  the union of natures, God to become man;  the union of grace, that we are one with Christ;  and the union of glory. The first is for the second, and the second for the third; God became man, that man might become one with God; God was ‘manifested in the flesh,’ that we might be united to him; and being brought again to God the Father, we might again come again to a glorious union.”
“By this, that God was ‘manifest in the flesh,’ it is that he was married first to our nature, that we by union might be married to him. We had never had union with God unless God had united our flesh to him, and in that flesh had satisfied God. All that Christ did, saith Peter, it was to ‘bring us back again to God,’ 1 Peter 3:18 [p. 480].”
This theme of marital union of believers with Christ shaped Sibbes’ mature theology. In his day some leading figures—including William Perkins—held humanity to be so different from God as to be kept at a metaphysical arms-length from him. This incommensurability of the Creator and his creation was an axiom of Classical Greek philosophy in both the Aristotelian and Platonic camps. And puritans were trained in Greek philosophy as a foundation for their theological studies.
Luther dismissed this premise but many Protestants accepted it. The marital imagery presumed an actual participation in the divine life through Christ that surpassed the doctrine of “imputation.” So, he and Sibbes believed, while God’s righteousness is certainly imputed to a believer, it is only a corollary to the bigger picture: God wants us to have communion with him by our “glorious union.”
The real question has to do with the question of ontology. Can we really be “united” with God in the terms Jesus seems to presume, for instance, in John 17? And that Peter seems to be saying when he speaks of our being “partakers of the divine nature” in 2 Peter 1:4?
Earlier in the series Sibbes addressed this tension. This truth, he believed, is “a mystery, and it must be unveiled by God himself, by his Spirit.” Yet a resistance to God’s revelation came about over time. “It was the fault of the schoolman [i.e. medieval scholastic theologians] in later times. They would come with their logic only and strong wits, and such learning as those dark times afforded, to speak of grace, of the gospel, of justification” [p. 467].
The key to God’s disregard of incommensurability, Sibbes held, is found in Christ’s incarnation. This certainty is the basis for all sound Christian faith: “That which reason should do here is to stoop to faith in things that are altogether above reason, as to conceive Christ in the womb of a virgin, the joining of two natures in one, the trinity of persons in one divine nature, and such like. Here it is the greatest reason to yield reason to faith” [p. 467]. So if Jesus is both God and man, so we are able to be united to God by faith in Christ.
God’s motive for this arrangement is love. “For the Spirit of God will tell us what is in the breast of God, his secret good-will to the church; he loves the church and he loves thee, saith the Spirit” [p. 469]. It was this truth, Sibbes held, that separated the Roman Catholic Church of his day from the insights offered by the Evangelical faith.
Sibbes’ claims here are still striking today for many. The claim that God’s love for believers is even more intimate and pure than the rich mutual devotion of a man and woman in faithful marriage is often hard to accept. Forgiveness of sins and imputed righteousness are much easier claims to accept than claims of marital union and metaphysical oneness that Luther and Sibbes promoted.
But the real question has to do with God’s revealed truth rather than with human reason. With that in mind let’s turn to the great forgiveness text of Isaiah 53 where God presents Christ as his suffering Servant:
“Surely he has borne our griefs and carried our sorrows; yet we esteemed him stricken, smitten by God, and afflicted. But he was pierced for our transgressions; he was crushed for our iniquities; upon him was the chastisement that brought us peace, and with his wounds we are healed.”
And then notice how this forgiveness is located in the broader vision of God’s ambition for his bride in the following chapter, Isaiah 54:5-7.
“For your Maker is your husband, the LORD of hosts is his name; and the Holy One of Israel is your Redeemer, the God of the whole earth he is called. For the LORD has called you like a wife deserted and grieved in spirit, like a wife of youth when she is cast off, says your God. For a brief moment I deserted you, but with great compassion I will gather you.”
Luther and Sibbes got it right. Imputed righteousness through Christ’s sacrifice is simply a means to the Father’s much greater project, to secure for his Son an everlasting, holy bride.