The poor monk, worn out with fatigue, was eager to seize any moment which he could steal from his servile occupations, and devote it to the acquisition of knowledge. Gladly did he retire into a corner, and give himself up to his beloved studies. But the friars soon found him out, gathered around him, grumbled at him, and pushed him away to his labours, saying, "Along! along! it is not by studying, but by begging bread, corn, eggs, fish, flesh, and money, that a friar makes himself useful to his convent."[152] Luther submitted, laid aside his books, and again took up his bag. Far from repenting of having subjected himself to such a yoke, his wish was to bring it to a successful result. At this period, the inflexible perseverance with which he ever after followed out the resolutions which he had once formed, began to be developed. The resistance which he made to rude assaults gave strong energy to his will. God exercised him in small things that he might be able to stand firm in great things. Besides, in preparing to deliver his age from the miserable superstitions under which it groaned, it was necessary that he should feel the weight of them. In order to empty the cup he behoved to drink it to the dregs. [152] Selnecceri Orat. de Luth. Mathesius, p. 5. This severe apprenticeship, however, did not last so long as Luther might have feared. The prior of the convent, on the intercession of the university of which Luther was a member, relieved him from the mean functions which had been imposed on him, and the young monk resumed his studies with new zeal. The writings of the Fathers, particularly those of Augustine, engaged his attention; the Commentary of this illustrious doctor on the Psalms, and his treatise "On the Letter and the Spirit," being his special favourites. Nothing struck him more than the sentiments of this Father on the corruption of the human will, and on Divine grace. His own experience convincing him of the reality of this corruption, and the necessity of this grace, the words of Augustine found a ready response in his heart; and could he have been of any other school than that of Jesus Christ, it had doubtless been the school of the doctor of Hippo. The works of Peter D'Ailly and Gabriel Biel he almost knew by heart. He was struck with a remark of the former--that had not the Church decided otherwise, it would have been much better to admit that in the Lord's Supper bread and wine are truly received, and not mere accidents. He likewise carefully studied the theologians, Occam and Gerson, who both express themselves so freely on the authority of the popes. To this reading he joined other exercises. In public discussions he was heard unravelling the most complicated reasonings, and winding his way through labyrinths where others could find no outlet. All who heard him were filled with admiration.[153]