One of the beneficial consequences of the recent debates surrounding reformed catholicity and the proper retrieval of the medieval theologians, such as Thomas Aquinas, is that increased numbers of people are digging into the original sources for themselves and finding the treasure of the “old paths” (Jer. 6:16) within the Great Tradition that permeated so many of the reformers, reformed orthodox, and the Puritans. For far too long, caricatures of the Reformation have dominated the evangelical landscape, leaving many valuable resources buried in its wake. Many fear that a deeper study of Aquinas and others will lead to many swimming the Tiber. There is, however, no reason to think that this will be the case. Many of our reformed forefathers engaged in a kind of retrieval of Aquinas and others, yet without converting to Roman Catholicism. We can look to them as models for our own day. One such forefather, is William Perkins.
William Perkins is considered by many to be the father of English puritanism. It would be difficult to oversell his monumental influence. Thomas Goodwin, a Westminster divine, wrote a generation after Perkins’s death that “the town was then filled with the discourse of the power of Mr. Perkins’ ministry, still fresh in most men’s memories.”  J.I. Packer writes that “no Puritan author save Richard Baxter ever sold better than Perkins, and no Puritan thinker ever did more to shape and solidify historic Puritanism itself.”  Needless to say, many of the puritans, including the members of the Westminster assembly were indebted to Perkins and his articulation of reformed theology. So how did Perkins approach theologians such as Aquinas? Was there a wholesale rejection of key doctrines or does this preeminent theologian serve as a model of true reformed catholicity? As we will see, the latter is true as Perkins gives us a model for reformed catholicity.
What does it mean to be a reformed catholic? For Perkins, a reformed catholic is “anyone that holds to the same necessary heads of religion with the Roman Church; yet so as he pares off and rejects all errors in doctrine whereby the said religion is corrupted.”  Perkins, like the reformers before him, held together two central ideas. First, the Roman Church has erred greatly and secondly, that “The abuse of a divine institution does not rule out its proper use.”  Therefore, since the Holy Spirit is the fountain of all truth, who leads us into all truth (Jn. 16:13), we should not shy away from those men who have taught the church faithfully in certain areas. Further, even if we believe some of the medieval schoolmen to be beyond the borders of orthodoxy, this would still not render them useless to the church. If we take the maxim that “all truth is God’s truth,” then those men who are made in the image of God and living under common grace can provide truths that are consistent with scripture. Even if we believe the men to be outside the true Christian faith, this does not negate truth.
I quote Calvin at length on this point:
Whenever we come upon these matters in secular writers, let that admirable light of truth shining in them teach us that the mind of man, though fallen and perverted from its wholeness, is nevertheless clothed and ornamented with God’s excellent gifts. If we regard the Spirit of God as the sole fountain of truth, we shall neither reject the truth itself, nor despise it wherever it shall appear, unless we wish to dishonor the Spirit of God. For by holding the gifts of the Spirit in slight esteem, we contemn and reproach the Spirit himself. What then? Shall we deny that the truth shone upon the ancient jurists who established civic order and discipline with such great equity? Shall we say that the philosophers were blind in their fine observation and artful description of nature? Shall we say that those men were devoid of understanding who conceived the art of disputation and taught us to speak reasonably? Shall we say that they are insane who developed medicine, devoting their labor to our benefit? What shall we say of all the mathematical sciences? Shall we consider them the ravings of madmen? No, we cannot read the writings of the ancients on these subjects without great admiration. We marvel at them because we are compelled to recognize how pre-eminent they are. But shall we count anything praiseworthy or noble without recognizing at the same time that it comes from God? Let us be ashamed of such ingratitude, into which not even the pagan poets fell, for they confessed that the gods had invented philosophy, laws, and all useful arts. Those men whom Scripture [1 Cor. 2:14] calls “natural men” were, indeed, sharp and penetrating in their investigation of inferior things. Let us, accordingly, learn by their example how many gifts the Lord left to human nature even after it was despoiled of its true good. 
This is not to say that one should approach the doctrines of the church at Rome uncritically. Far from it, as Perkins readily points out that “it is a notable policy of the devil, which he has put into the heads of sundry men in this age, to think that our religion, and the religion of the present Church of Rome are all one for substance; and that they may be reunited as (in their opinion) they were before.”  So, what are some areas where we can rightly appropriate Aquinas and receive his teachings without the fear of “swimming the Tiber?” Typically, most would immediately point to the doctrine of the Trinity. This is a great and true example. However, I want to point briefly to one area that is characteristic of the reformed tradition: predestination.
Recently, some have argued that the reformed doctrine of predestination and that which is found in Aquinas are irreconcilable, since it is Thomistic theology that underlies the Council of Trent. At first glance, it seems that Perkins would agree with these modern critics when he says that Rome’s doctrine is “surely a very blasphemous doctrine, and no better to be accounted of than as a gallows set up for the torture and massacre of men’s consciences.”  Yet, what we actually find is his employment of men like Aquinas in his polemic against Rome (and others) in the doctrines of predestination.
In the course of his treatment of predestination, Perkins takes up several objections, one of which is that seemingly a large portion of mankind is devoid of all saving grace. In his reply, Perkins appeals to particular redemption. He says that “we do acknowledge with glad minds that Christ died for all (the scripture averring so much); but we utterly deny that he died for all and every one alike in respect of God, or as well for the damned as elect, and that effectually on God’s part.” 
As he answers this objection, Perkins directly quotes from the Summa, stating that “Aquinas says ‘Christ’s merit according to the sufficiency of carries itself indifferently to all, but not according to the efficacy. Which happens partly by God’s election, through which the effect of Christ’s merits is mercifully bestowed on some, and partly by the just judgement of God withdrawn from others.’” 
Nor is this use of Aquinas an isolated incident. In fact, Perkins draws from Thomas again in arguing against John of Damascus, who had argued that the will of God should be divided into two parts, the precedent and consequent. His precedent will is that willing to bestow all good things, including salvation to all men. God’s consequent will is that for some certain circumstances he absolutely wills that man should be damned. Setting Thomas against John of Damascus, Perkins says “I oppose Thomas Aquinas against him, who says, ‘But says some man, God loves all men. Where to I answer that it is true so far forth as He wills some good to all…And therein He is said to hate and reject them.’”  To further bolster his argument, he also includes quotes from Augustine, Remigius, Bernard of Clairvaux, Haimo, and others.
For Perkins, these men, at least on certain issues, were faithful to Scripture and so are to be read, utilized, and employed in the defense of the reformed faith. He sees no issue in applying the teaching of Aquinas on predestination against an ancient church father. How is he able to cite all of these men in defense of the reformed faith without a hint of irony or self-contradiction? He does so because he was a reformed catholic who recognized that to be reformed is not to sever yourself from medieval predecessors, but to press deeper into true catholicity.
In this way he serves as a model for us today. This is precisely how one should approach the great tradition. We receive that which has come down from the school of Christ in agreement with Scripture, using it to promote truth and refute error.
Derrick Brite is the pastor of First Presbyterian Church (PCA) in Aliceville, Alabama, and a PhD candidate in systematic theology at Puritan Reformed Theological Seminary.
  As Citied in Garnet Howard Milne, The Westminster Confession of Faith and the Cessation of Special Revelation: The Majority Puritan Viewpoint on Whether Extra-Biblical Prophecy is Still Possible (Eugene, OR: Wipf and Stock Publishers, 2008), 49.
  J.I Packer, Puritan Portraits (Ross-shire, U.K.: Christian Focus Publications, 2012), 130. Kindle.
  William Perkins, “A Reformed Catholic” in The Works of William Perkins, Vol. 7, eds. Shawn D. Wright and Andrew S. Ballitch (Grand Rapids, MI: Reformation Heritage Books, 2019), 5.
  Michael Allen and Scott R. Swain, Reformed Catholicity: The Promise of Retrieval for Theology and Biblical Interpretation (Grand Rapids, MI: Baker Academic, 2015), 21.
  John Calvin, Institutes of the Christian Religion, trans. McNeill & Battles (Louisville, KY: Westminster John Knox Press, 2011), 1.273-275.
  Perkins, “A Reformed Catholic”, 4.
  William Perkins, “A Golden Chain” in The Works of William Perkins, Vol. 6, eds. Joel R. Beeke and Greg A. Salazar (Grand Rapids, MI: Reformation Heritage Books, 2018), 223.
  William Perkins, “The Manner and Order of Predestination” in The Works of William Perkins, Vol. 6, eds. Joel R. Beeke and Greg A. Salazar (Grand Rapids, MI: Reformation Heritage Books, 2018), 338.
  Ibid., 341.
  Ibid., 346.