The Erfurt Augustinians belonged to the strict section of the order, in contrast to the Conventuals or laxer section. After a year's novitiate Luther took the vows of obedience, poverty and chastity, and submitted to the drudgery which was an essential part of his training. Under his preceptor, Nathin, he then went through a course of theological instruction in preparation for his ordination as priest, which took place in 1507. Thereafter he continued his theological studies for the degrees of biblical bache lor and master of the sentences (Sententiarius), or dogmatic theology, as expounded in the Sentences of Lombardus, attending the lectures of the theological faculty of the university as well as the theological school of the monastery. In accordance with the prescribed course, he studied the Bible, the Sentences, and the works of Occam, and his disciples D'Ailly and Biel, and dipped into those of St. Bernard, Duns Scotus, and Augustine. He con tinued these studies at Wittenberg, where he spent a year from the autumn of 1508 to that of 1509 as lecturer on Aristotle's Ethics, and where he enjoyed the personal intercourse of John Staupitz, professor of theology and vicar-general of his order. On his return to Erfurt he obtained the degree of sententiarius, and began to lecture on the Sentences. The books which he read in his preparation of these lectures were discovered in the library at Zwickau in 1889, and contain on the margins a large number of notes (given in vol. ix. of the Weimar edition of his works) in his own handwriting, which throw light on his theological and philo sophical thought and standpoint at this stage of his development. Whilst displaying a critical, enquiring mind, they show no mate rial departure from the scholastic method and the scholastic theology in its Occamist form, though some modern theologians like Seeberg find evidence in them of a distinctive divergence from his theology. At most they reveal a growing predilection for the teaching of Augustine.
This lectureship he filled till the late autumn of 1511, when, at the instance of Staupitz, he was transferred to the monastery at Wittenberg, of which he was ere long appointed sub-prior at a meeting of his order at Cologne in the following year. In Oct. 1512 he took the degree of doctor of theology of the university and became the successor of Staupitz as professor of biblical literature. Towards the end of 1510 he had paid a short visit
to Rome on business connected with his order, and though his visit was that of the devout pilgrim, he appears to have been painfully impressed by the secularized ecclesiasticism and the low moral standard of the Holy City. There is, however, no evi dence for the oft-repeated statement that the discovery of his distinctive doctrine of justification by faith came to him as he climbed on his knees the steps of the Scala Sancta at the Lateran church.
The root of this struggle to find a gracious God lay in his personal temperament, his lofty religious and moral ideal and in the religious. the practical, and the theological teaching of the mediaeval Church. In temperament he was high-strung, emotional, impressionable, and liable to fits of depression which took at times an acute form. He had a sensitive conscience and a keen sense of sin, which the meticulous observance of the rule of his order only tended to intensify. To him sin and the sinful tendency (con cupiscence) were terrible realities in keeping with his exalted conception of God as perfect righteousness and the retributive character of this righteousness (justitia Dei), which impels Him to judge and condemn the sinner, and which was emphasized in the teaching and practice of the mediaeval Church. How to attain to the ideal divine righteousness and, thus enter into a proper relation of acceptance and fellowship with God, and thereby also ensure salvation from the Divine retribution for sin, was the problem that obsessed him and led to this recurring spiritual conflict (Anfechtungen). In the sacrament of penance the Church sought to ensure the penitent sinner against this retribution by imposing penitential works in satisfaction for sins. Luther, however, could not be sure of the sufficiency either of his contrition or of his penitential satisfaction in spite of official absolution. The Church further sought to ensure the sinner against the Divine judgment by its doctrine of merits, based on the relative freedom of the will to do the good whereby, with the aid of God's grace, he could conciliate the Divine favour on the day of judgment. Here again Luther, conscious of the weakness of the will to attain the absolute good which alone could avail in the sight of a perfectly righteous God, failed to find the assurance of salvation in this teaching. In addition he was distressed over the doctrine of predestination; which had for him not only a speculative, but a religious signifi cance. How could he be sure that he was among the number of the elect whom God had predestined and chosen, according to the Occamist teaching, by an act of his absolute, arbitrary will.