According to a pseudonymous author, 1978 was the year Reformed theology changed:
Reformed theology has changed. And there seems to be no going back. It was in the year 1978 that a tectonic shift in the underlying structure of Reformed theology began with the publication of a small book. The changes were not only systematic, but also systemic—affecting all aspects of it. Yet, interestingly, the changes were initially imperceptible until several years later.
Dr. Richard Gaffin, of Westminster Theological Seminary published his first book, The Centrality of the Resurrection, which would later be renamed and mass published under the title Resurrection and Redemption: A Study in Paul’s Soteriology. It was in this fine exegetical work that Dr. Gaffin unpacked the meaning of the Apostle Paul’s salvation vocabulary. Words like justification, sanctification, adoption, etc. would be understood differently in light his research. Dr. Gaffin was building upon historical Reformed theology as well as critiquing it. To do this he was deeply influenced by the work of various theologians across denominational distinctions, and in particular he was shaped by Reformed thinkers such as Herman Ridderbos and John Murray. But in the end, Dr. Gaffin would put together the exegetical conclusions in a way that had never been done before.
A recovery of union with Christ could have led to a higher view of the sacraments, the way it did for John Williamson Nevin, who also stressed union with Christ:
Most people are taught in Reformed churches and seminaries, to think linearly about salvation (e.g. Justification leads to Sanctification which leads to Glorification). A person is first justified (i.e. saved, forgiven) and then comes sanctification (i.e. growth, maturity), and then comes glorification (i.e. dying and rising from the dead at the resurrection). Other words may be added to this order of salvation (e.g. regeneration, adoption, etc.) but the historical way of looking at these words fits them in an unbreakable, linear, “golden” chain. This is called the ordo salutis (Latin term: “order of salvation”). It’s the Reformed way of explaining the application of salvation to a person from beginning to end. Once a person is justified, the other benefits follow in due course. If a person is “truly” justified, the rest will follow.
This is one reason why Reformed theology has always struggled to “fit” the sacraments into any meaningful place in its systematic theology. If the golden chain of salvation can’t break, then it’s difficult to see how baptism is really all that important or why the Lord’s Supper is necessary. While Reformed theology held to the Lord’s Supper as a “means of grace” it was rare to find a Reformed church practice weekly communion or place it on par with preaching. The sacraments were aids to faith–crutches if you will–but not really necessary in the life and practice of Reformed churches considering the logical consequences of the “golden chain.” If you focus on the linear progression of the ordo salutis, the unbreakable chain of salvation, starting with predestination and ending with glorification then, the sacraments have little need in such a theological system, logically and practically speaking.
But that isn’t where Dr. Gaffin wanted union to go:
But if soteriology is eschatology, then doesn’t soteriology also include the restoration and renewal of personal relationships in a new community? If that’s the case, then isn’t soteriology also ecclesiology? This conclusion, in particular, the “New Gaffin” in his By Faith would attempt to avoid in order distance himself from the sacramental and ecclesiological implications. While many scholars and theologians were coming to this particular conclusion, Dr. Gaffin was distancing himself away from the conclusion that soteriology is ecclesiology.
But despite his attempts to ward off the conclusions, there were clear biblical arguments that couldn’t be avoided by many. Baptism engrafts into Jesus Christ. As Dr. Gaffin had originally said, “…if ‘washing’ on which ‘regeneration’ is directly dependent in Titus 3:5, refers to baptism, then what Romans 6:3ff…teaches concerning baptism as a sign and seal of incorporation with the resurrected Christ, and so the implications of that incorporation, will have to be brought to bear here.” The implications were clear to many: All the benefits of salvation are given in baptism because baptism engrafts into Christ. Soteriology didn’t simply have “implications” on ecclesiology; it is ecclesiology. To be baptized into the Christian church is to be baptized into Jesus Christ.
In which case, how revolutionary was the recovery of union with Christ? Did its advocates simply tinker with the ordo salutis or did they seek to apply union to ecclesiology, liturgy and the sacraments? From this seat, it looks like union had a narrow application, chiefly to a discussion of the application of redemption that comes up in questions 29 through 38 in the Shorter Catechism. For union to apply to questions 88 through 97, unionists would need the Federal Visionaries.