For John Wesley there were a number of turning points by which he gained new insight that decisively shaped not only his theology but his life. This year in Consider Wesley I want to describe four of those life-changing events.

The first of these rivals his famous attendance at the meeting on Aldersgate Street in significance if not in drama. It occurred when as a student at Oxford in 1725 the twenty-two-year-old Wesley read two books that changed his life: The Imitation of Christ by the medieval mystic Thomas à Kempis (1380–1471) and Rules and Exercises of Holy Living and Dying by Church of England Bishop Jeremy Taylor (1613–1667).

In his A Plain Account of Christian Perfection (1766) Wesley describes the impact these two books had on him. Reading Taylor, “I was exceedingly affected; that part in particular that relates to purity of intention. Instantly I resolved to dedicate all my life to God, all my thoughts, and words, and actions …” (§2). Kempis confirmed and deepened that resolve: “The nature and extent of inward religion, the religion of the heart, now appeared to me in a stronger light than ever it had done before. I saw, that giving even all my life to God … would profit me nothing, unless I gave my heart, yea, all my heart, to him” (§3).

Without “‘simplicity of intention, and purity of affection,’ one design in all we speak or do, and one desire ruling our tempers,” Wesley believes our souls can never ascend to God (§3). The language of “purity of intention” or “one desire ruling our tempers” refers to the dispositions of the heart. Another way Wesley will speak of this is holiness of heart, which, because it governs our motives and desires, leads to holiness of life.

Wesley delves more deeply into the Scriptures as well as continues reading more “holy living” writers, looking for advice on how to shape and discipline his life to attain this goal. In particular, he highlights a third author as especially contributing to his search for purity of heart, his older contemporary Willian Law (1686–1761). The books were Law’s A Serious Call to a Devout and Holy Life and A Practical Treatise on Christian Perfection. “These convinced me, more than ever,” wrote Wesley, “of the absolute impossibility of being half a Christian, and I determined, through this grace, (the absolute necessity of which I was deeply sensible of,) to be all-devoted to God …” (§4).

These are the roots of Wesley’s doctrine of Christian perfection, easily his most controversial teaching but also the one more than any other that governs his understanding of Christian salvation. In Wesley’s mature theology, to attain Christian perfection is to be renewed in the divine image; it is to love God wholly and unreservedly, and to love our neighbor as ourselves. Wesley develops the most theologically developed, thoroughly Protestant version of this Christian perfection tradition.

To do this Wesley will come to define Christian perfection not as absolute perfection but, in accordance with its Greek linguistic roots, as perfection with regard to a goal, which in this case is love. He will further distinguish between intentional sin, which has to do with the dispositions of the heart, and involuntary transgressions, in which through ignorance or other limitations our actions fail to fulfill the will of Good. Christian perfection purifies the intentions of the heart but does not prevent us from actions that unintentionally violate God’s will.

His more immediate problem from 1725 to 1738 is that he believes attaining purity of heart is necessary to have assurance of salvation. To resolve this issue, he will need to distinguish more clearly justification from sanctification, and new birth from Christian perfection, as well as make room for a much more robust understanding of the divine initiative in the cross of Christ and the power of the Holy Spirit.

But he will never abandon the centrality of Christian perfection in his theology. In September 1790, less than a year from his death, Wesley says of Christian perfection: “This doctrine is the grand depositum which God has lodged with the people called Methodists; and for the sake of propagating this chiefly he appears to have raised us up” (Letter to Robert Carr Brackenberry, 15 September 1790). It was and remains at the very heart of Wesleyan Christianity.