There is no question that a difference in emphasis exists between the Reformers and the English and New England Puritans over the question of assurance. The Reformed tradition in Europe, in agreement with Calvin's exegesis, argued that assurance is the essence of faith. In other words, to trust in Christ is to have the assurance that "there is therefore now no condemnation." If saving faith is more than the conviction that Jesus Christ died on the cross and rose from the dead, but that he did this for me, then that conviction is synonymous with assurance. To trust in Christ alone for salvation is to be assured that he will fulfill his promise. If we are not assured, we are not trusting.
Of course, this was never to suggest that assurance is complete, any more than faith. Our faith and assurance may be weak, sometimes barely distinguishable, but it is impossible to truly exercise a justifying faith that does not contain the assurance that Christ's saving work has guaranteed what has been promised in one's own case.
In the Puritan context, however, the Reformed doctrine of assurance underwent a slight shift in emphasis. The Reformation had been a biblical response primarily to legalism, as justification in the medieval church was confused with sanctification and assurance was impossible because being rightly related to God depended on whether one cooperated with grace from day to day. The Reformers rightly emphasized the objective character of the gospel: Christ crucified outside of my own personal experience and behavior, two thousand years ago, as a once-and-for-all satisfaction of divine justice in my place. But before a generation passed, there were those who had embraced the Reformation because they saw in it an opportunity to be saved by what we today might call "easy-believism." All they had to do was assent to the teachings of the Reformed or the Lutheran churches, just as they had to the Roman church, and they could be "safe and secure from all alarm." Although the Reformers protested that this was merely "devil's faith," the stuff of which hypocrites were made, it seemed that the profession of these growing ranks of hypocrites risked proving Rome's point, that the evangelical doctrine promotes license and presumption.
It was in this setting that the English Puritans pastored, convinced that the believer's inner life, the ministry of the Holy Spirit, and the concerns of piety had been almost abandoned by those who, in fleeing Rome for the Reformation, had merely leaped from the frying pan into the fire. Even though the Puritans shared an identical theological system with the Reformed on the continent of Europe, the former insisted that it is a mistake to say that assurance is of the essence of faith. In one case, it encourages presumption among the hypocrites who think they are justified even though there are no fruits; in the other, it creates anxiety among those who, instead of worrying about whether they have enough works, are now wondering if they have enough assurance! Calvin insisted that it is not the degree of faith or assurance that secured justification, but even the weakest grasp of faith, like the father of the demon-possessed son, who replied to Christ's invitation to believe with moving honesty: "Lord, I believe; help my unbelief!" (Mark 9:24). Nevertheless, the pastoral setting provided for a variety of applications and Puritanism on this score was a deviation, not from the theology of the Reformation, but from the practical pastoral counsel on the matter of assurance. For instance, few leaders from the Continental Reformed side of the assurance question were as intimately associated with the English Puritans as Zacharias Ursinus (1534—83), principal author of the Heidelberg Catechism. And yet, Ursinus, following Calvin's line, argued from a number of texts, "No man can indeed know, or judge with certainty from second causes [i.e., the fruit of conversion], or from events whether good or evil; for the external condition of men furnishes no safe criterion either of the favor or disapprobation of God....We may therefore be ignorant of our salvation, as far as it is dependent upon second causes, but we may know it in as far as God is pleased to reveal it unto us by His Word and Spirit."
This did not mean that one could not use evidences of true conversion to support one's assurance; nor did it mean that one could never be without such evidences. Even in committing great sinful acts, the truly converted man or woman is sorrowful and repentant. Nevertheless, it is always dangerous to build one's assurance on a foundation of works, even though one denies the place of works in justification.
As the Heidelberg Catechism is the most important representative document from the Continental consensus, so the Westminster Confession and Catechisms is the principal document from the Puritan and Presbyterian side of the assurance question. Again, this is not a matter of doctrine so much as of practical pastoral application of doctrine. Nevertheless, the shift from warning believers against introspection in an effort to discern evidences to encouraging it was very important practically. If assurance is not of the essence of saving faith, and it can be lost because of sin, sensitive persons will inevitably scrape their consciences raw until they find clues and, as Calvin warned, there will be no satisfaction with evidences; there will never be enough to secure the soul's confidence.
— Michael Horton, "Christ Crucified between Two Thieves," Christ the Lord (The Reformation and Lordship Salvation), ed. Michael Horton (Eugene, OR: Wipf and Stock, 1992), 132—134 (italics original).
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It must be remembered, however, that Puritanism was a diverse movement. The leading figures—Perkins, Owen, Ames, Goodwin, Sibbes, and Hooker, were Reformed pastors who simply wanted to breathe new life into "dead orthodoxy," by showing how the objective work of Christ for us related to the subjective work of Christ in us...For the Reformers, and for the better Puritans, the accent fell on judicial verdict, not moral renewal, although both were clearly taught as inseparable acts of God.
— ibid., 140—141.
