None of us knows the specifics of the future. There are a few things that every Christian knows from Scripture about the future. We know that Christ shall return (Acts 1:11), that there shall be a bodily resurrection (1 Thess 4:16), and after that the judgment (Rom 14:10). The future, of course, is in the good, sovereign and merciful hands of our triune God (Heidelberg Catechism 27). Believers know that whether we live or die, we are the Lord’s (Rom 14:8; Heidelberg Catechism 1). There are other things about which believers have certainty, but much of the future, from a human perspective, is a matter of probabilities. These we can determine from history.
Perhaps the greatest threat to the early post-apostolic church was that of Gnosticism, a second-century (100s AD) movement that drew on threads in pre-Christian pagan philosophy to create a heresy of the Christian faith. The Gnostics denied the goodness of creation per se, the validity and truth of the Hebrew Scriptures, and the true humanity of Christ (among other things). The Gnostics specialized in filling in the blanks. Where the gospels maintained a reverent silence about the infancy of our Lord Jesus, the Gnostics filled in the story with myths. Where the gospels were silent about our Lord’s life between his appearance in the temple and his baptism, the Gnostics filled in the story. They peddled myths about the hierarchies of being and sought to turn the biblical picture of the world on its head. They offered salvation through secret knowledge (gnosis). One movement led by a pastor’s son, Marcion, which broke away from the Gnostics, flourished for about 300 years. The early Christian apologists, e.g., Irenaeus and Tertullian, spent much time and ink defending orthodox Christianity against the Gnostics and the Marcionites.
If some of this sounds familiar, it should. Versions of this competing religion have become widely popular both among the new pagans but also in some ostensibly Christian circles. Otherwise Bible-believing evangelicals regularly speak about the Old Testament (the Hebrew and Aramaic Scriptures considered as a whole) in ways that are not far distant from the ways that Marcion spoke about them. Christians regularly appeal to secret or esoteric knowledge in ways that are quite reminiscent of the Gnostics.
Every indication is that we will continue to see claims from the culture, fed by neo-pagan antipathy to orthodox Christianity, such as those made by Dan Brown and even by some scholars who should know better about competing “gospels” (e.g., the so-called “Gospel of Jude”) or competing “epistles,” which give the impression that the formation of the New Testament was arbitary and political when the evidence points us in exactly the opposite direction.
From the beginning of the church there have been those within its pale who have been a little uneasy with the gospel of free salvation by grace alone, through faith alone. Even though the early church was relatively clear about this, when our better writers addressed it (e.g., the Letter to Diognetus, c. 150 AD, or Augustine’s anti-Pelagian writings in the early 5th century), there were always those who wanted to make salvation conditional upon our performance. That story, “in by grace, finish by cooperation with grace,” became widespread in the medieval period. Of course, it was overthrown in the Reformation but almost as soon as the gospel was recovered, some starting chipping away at it even within Protestantism. Some undermined it by denying that believers must give evidence of new life and true faith by seeking to bring their lives into conformity with God’s holy law. The 1520s were marked by an “antinomian” crisis. Indeed, it was Martin Luther himself who coined that word to describe those who denied the abiding validity of God’s law. In the following decades others chipped away at the gospel from the other direction by implying that salvation begins by grace alone (sola gratia), through faith alone (sola fide) but is ultimately contingent upon our good works. In the 17th century, the Remonstrants (Jacob Arminius, et al) added conditions to election and to salvation. Richard Baxter (1615–91), whom J. I. Packer rightly calls a “neonomian” (a new legalist) openly taught that faith justifies, not because it rests in Christ’s finished work, but because it obeys God’s law. John Owen devoted an entire volume (5) of his Works to refuting his errors on justification. Today, however, Baxter is presented to us as an orthodox Reformed pastor and readers and students are shocked to find that he openly denied the gospel.
Indeed, in some quarters today, even as we just celebrated the 500th anniversary of the Reformation, there were leading evangelical and even Reformed and Presbyterian Christians advocating a doctrine of two-stage salvation or justification. An initial justification by grace alone, through faith alone, and then a so-called “final salvation” or “final justification” through faith and works. History tells us that we must re-learn and defend the gospel in every generation. My experience tells me that it has to be done at least every ten years. Luther said that he preached the gospel every week because people forget it from one Lord’s Day to the next.