Martin Luther’s Discovery: The Late Medieval Background

In 1545, Martin Luther wrote the preface for the publication of his complete works in Latin.  Therein he included a biographical statement that included his recollection of how he rediscovered the doctrine of justification by faith alone.  He wrote:

At last, by the mercy of God, meditating day and night, I gave heed to the context of the words, namely, “In it the righteousness of God is revealed, as it is written, ‘He who through faith is righteous shall live.’”  There I began to understand that the righteousness of God is that by which the righteous lives by a gift of God, namely by faith.  And this is the meaning: the righteousness of God is revealed by the gospel, namely, the passive righteousness with which merciful God justifies us by faith.[1]

While he wrote this almost 30 years after the events took place, his memory seems remarkably accurate based on the opinions of most scholars.  In a series of posts, I will attempt to give a short historical and theological examination of how Dr. Luther’s breakthrough took place.  In this post, I will focus on the late medieval teachings on justification, salvation, faith, love, and good works.

When Martin Luther became a doctor of theology at Wittenberg in October 1512, he was a typical religious professor in late medieval Germany.  However, five years later, he instigated the Indulgence Controversy that led to a theological revolution.  Dr. Luther belonged to a religious order, the Observant Augustinians, which supplied professors to the university in Wittenberg.  Additionally, in 1514 he became a regular preacher in the city church.  His duties as a professor and preacher compelled Luther to study intently the Bible and the writings of significant Christian theologians.[2]

Since the late twelfth century, scholastic theologians had synthesized Aristotle’s philosophy with Christian theology.  In his Sentences, Peter Lombard (d.1160) compiled the most significant theological commentary of the Middle Ages.  It remained the standard textbook of theology into the sixteenth century.  Every major theologian, including Luther, studied it closely and many wrote commentaries on the Sentences.  Early scholastic writers, like Peter, pondered how grace could be present in a human soul.  In other words, how could the sinner become righteous before God and appropriate divine salvation exemplified in Christ’s divine love?

Peter Lombard answered this question by equating the indwelling Holy Spirit with divine love.  Augustine had identified the Spirit as the love of the Father and the Son.  Based on this idea, Lombard wrote, “It must be added to this that the very same Holy Spirit is the love or charity by which we love God and neighbor.”[3]  Lombard equated the love poured into believer’s hearts in justification with the Holy Spirit who then works in and through the believer.  After stating that the gift of Holy Spirit separated the saved from the damned, Lombard concluded, “unless the Holy Spirit is given to each so as to make him love God and neighbor, he is not moved from the left hand to the right hand.”[4]

Lombard’s understanding of divine love paralleled his teaching on grace and free will.  He taught that the Son must liberate sinners and repair them by grace for them to act justly.  According to Peter, the natural human lacked the ability to will the good without the liberation of grace.  Citing Romans 9:16 and Philippians 2:13, Lombard explained, “It is not the will or work of man which calls upon God’s grace, but grace itself first comes the will, preparing it to will the good, and then aids the prepared will to achieve it.”[5]  In the following distinction, he stated that this prevenient grace is faith with love (citing Gal. 5:6) and it is this very faith that is the “cause of justification.”[6]

Peter Lombard stated plainly that only God works righteousness in human beings and he does so by giving them FAITH (citing Ephesians 2:8).  Peter Lombard identified two types of grace: the uncreated grace of God and the grace of justification.  The first type of grace works to change the will of human beings so that they might work with the second grace and possess a good affection and good movement of the mind (virtue).  It was only through faith that the liberated will may generate a good and rewarding movement of the mind (virtue).  Thereby, God’s grace, that is, his charity (caritas) moves the mind to love (diligere).  According to Lombard, God makes the virtues because even though human beings cooperate through the will, only God “frees and aids the choice with his operating and cooperating grace.”[7]

Although Lombard distinguished between God as love or grace and the virtue exercised by the free will of human beings, he did not clearly define the differences.  We must remember that scholastic theology represented an ongoing project in the twelfth century not a finished product.  After the recovery of Aristotle’s philosophical writings in the late twelfth century, scholastic theologians began to use these texts to explain theology.  Most significantly, they used Aristotle’s understanding of ethics to explain how grace works through love in the human soul.  The famous scholastic theologian, Thomas Aquinas, fully embraced Aristotle’s philosophy for this purpose.  After joining the new religious order, the Dominican Order of Preachers, he became an accomplished master of theology.[8]

Thomas demonstrated his integration of faith and reason by rejecting Lombard’s identification of the Holy Spirit with the love by which sinners may obtain salvation.  Aquinas argued that in order for divine love to be effective it must be voluntary.  Therefore, if the Holy Spirit worked directly upon the soul an act of love could not be voluntary.  He asserted that God creates love and grace in human souls as a disposition (habitus).  In the Summa Theologiae Aquinas explained, “And because grace is above human nature, it cannot be a substance or a substantial form; it is rather an accidental form of the soul.”[9]

Thomas also expanded Lombard’s Augustinian distinction between operating and co-operating grace.  Aquinas explained that grace might be understood as a divine assistance to will or act as a habitual gift from God. Both types of grace may be divided into operating and co-operating grace.  God’s operating grace moves the will to interior action which moves the will to outward act via co-operating grace.  Aquinas achieves his main theological innovation regarding the appropriation of salvation in his discussion of habitual grace.  As this disposition of grace heals and justifies the soul, then it is operating grace.  However, the habitual grace functions as the principle of meritorious action that proceeds from one’s liberated will.[10]

What does this mean for the appropriation of salvation to the individual sinner? Aquinas does have an extended section on the doctrine of justification in the Summa.  He identified four things as necessary for the justification of the ungodly: an infusion of grace, a movement of the will toward God by faith, a movement away from sin by the free will, and the remission of guilt.[11]  Aquinas also made it clear that charity must form any movement of faith for it be perfect.  This faith formed by love expressed through good works received eternal life as full merit (meritum de condigno).  That is, God infuses the soul with a disposition (habitus) of grace that inspires the believer toward love and thus to rightly earned merit for eternal life.[12]

While Aquinas influenced the development of scholastic teaching on justification, others challenged or modified his ideas in the late Middle Ages.  Franciscan theologians, such as, Duns Scotus (d.1308), believed Thomas gave too much credit to human disposition despite his emphasis on infused grace.  Scotus asserted the traditional Augustinian teaching on God’s predestination and grace.  For him, God’s will was the necessary basis of salvation even if He chose to use secondary instruments like sacraments or infused grace.  While God does accept the human disposition of charity, he does so contingently, not out of necessity.[13]

William of Ockham, a radical Franciscan, followed Scotus’ defense of God’s will, but made an important distinction between God’s absolute power and his ordained power.  Scholars identify him as a primary founder of the via moderna in late medieval scholastic theology. Ockham saw no intrinsic value in a disposition of grace formed by divine charity.  Ultimately, God ordained to save whom and how He so desired.  According to William, God had ordained to save or justify sinners through the means of a disposition of love inspired by grace.  However, he did so because he promised to do so.  In fact, Ockham, despite his emphasis on divine power, stated that God had made a covenant with human beings to accept their best natural efforts as reason to infuse grace into the soul.  Theologians called this an act of partial merit (meritum de congruo)[14]

The fifteenth-century German theologian, Gabriel Biel, followed Ockham’s views regarding penance and justification.  In his great mercy, God has chosen to reward those who do what is in them.  While sinners cannot obtain grace on their own, they may strive in their natural abilities to love God and reject sin.  Every human being has a natural knowledge of God and knows he should turn toward God.  When one acts in this innate knowledge and turns toward God, He rewards this action with grace.  Then the believer may cooperate with the grace to complete his faith with the disposition of charity.[15]

In his first series of lectures on the Psalms (1513-1515), Martin Luther explained justification in a manner consistent with the late medieval theological tradition.  He taught that humans did their best with their natural abilities through humbling themselves before God for which He agreed to reward them with grace.  While he did use the term righteousness of faith, Luther believed this righteousness originated from the divine agreement to reward the humility of sinners.  By the end of 1515, Luther’s views of justification began to change as demonstrated by his lectures on Romans.[16]

[1] Martin Luther, Preface to His Complete Latin Writings, AE 34:337.  There’s also an online version: (different translation)

[2] Martin Brecht, Martin Luther: His Road to Reformation, 1483-1521, trans. James L. Schaaf (Minneapolis 1985), 125-127 (receiving the doctorate), 150-151 (preacher); James M. Kittelson, Luther: The Reformer (Minneapolis 1986), 83-86.

[3] Peter Lombard, Sentences, Book 1, dist. 17, chap. 1.2  Cf. Alistter McGrath, Luther’s Theology of the Cross (Oxford 1985), 82-84; Steven Ozment, The Age of Reform (New Haven 1980), 31.

[4] Lombard, Sentences, Bk 1, dist. 17, chap.1

[5] Lombard, Sentences, Bk 2, dist. 25, chaps. 8-9.

[6] Lombard, Sentence, Bk 2, dist. 26, chap. 3.

[7] Lombard, Sentences, Bk 2, dist. 25, chaps. 1-8 (quote in chap. 8)

[8] Alister McGrath, Iustitia Dei, 2nd ed (Cambridge 1998), 63.  Aquinas wrote a commentary on Aristotle’s Nicomachean Ethics.

[9] Thomas Aquinas, Summa Theologiae Part II-1, Question 110, art. 2, resp. 2; Ozment, Age of Reform, 31-33.

[10] Aquinas, ST. Part II-1, Question 111, art. 2; McGrath, Iustitia Dei, 106-07.

[11] Aquinas, ST. Part II-1, Question 113, art. 6.  McGrath, Iustitia Dei, 44-46.

[12]  Aquinas, ST. Part II-1, Question 113, art. 4; Ozment, Age of Reform, 233.

[13] Ibid., 33-35.

[14] Ibid., 37-39; 233-34. Heiko Obermann, The Reformation: Roots and Ramifications (Grand Rapids 1994), 104-05.  On Ockham’s place in the via moderna see McGrath, Luther’s Theology of the Cross, 53-63.

[15] Carter Lindberg, The European Reformations: Sourcebook (Blackwell 2014), 14; Ozment The Age of Reform), 233-234;  Heiko Obermann, The Harvest of Medieval Theology (Durham 1983), 175-76; McGrath, Luther’s Theology of the Cross, 104-05.

[16] McGrath, Iustitia Dei, 190-193.  For a detailed examination of Luther as a late medieval theologian, see Idem, Luther’s Theology of the Cross, 72-92.



1 thought on “Martin Luther’s Discovery: The Late Medieval Background

  1. Dr. Phillips (or anyone else, for that matter),
    Is there a thorough commentary that covers every thesis of the Disputation Against Scholastic Theology?

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