In the year 1501, Luther arrived at the University in Erfurt, then the most distinguished in Germany. He had reached his eighteenth year and entered with great eagerness into the studies of manhood. "My father," says Luther, "maintained me there with much love and faithfulness, and supported me by the sweat of his brow." One of his biographers, moralizing on this grateful record of the son, observes: "And assuredly all the volumes of the history of mankind contain no record of a parent's manual toil being recompensed by so glorious a harvest as that which sprang from the persevering industry of the miner of Mansfeld. Every drop that fell from that brow was converted by a watchful providence to the furtherance of its purposes, and made the means of fertilizing the mind, which it had ordained to change the predominant principles of the christian world."
There is reason to believe that other thoughts besides the cultivation of his intellect were exercising the mind of Luther at this time. The merciful intervention of God in the kindness of the Cotta family, and what he had seen and learned there, made a deep and lasting impression on his inmost soul. He strongly objected to the study of Aristotle, although his system was in great repute at the college, and represented as the best, or rather the only, discipline for his reason. "Had Aristotle not been a man," he used to say, "I should not have hesitated to take him for a devil;" so great was his aversion to the philosophy of the learned Greek. The works of the great scholastics of former ages, such as Scotus, Aquinas, Ockham, and Bonaventura, were recommended to him as the only means of piety and learning; but these, for meeting the need of a troubled conscience, were little better than the logic of Aristotle. Nevertheless, in the wisdom of God, it was necessary that he should become conversant with these writings that he might be the better able, and have the better ground, to expose their utter worthlessness as to the service and worship of God. He also studied the best Latin authors, and, being blessed with great powers of penetration, perseverance, and a retentive memory, he made rapid progress in his studies, and early acquired the reputation of an expert and skilful dialectician.
In the year 1503 he took his first academical degree of Bachelor of Arts; and in 1505, he took that of Doctor in Philosophy. Having made considerable proficiency in several branches of literature, he began, in obedience to his father's wishes, to turn his attention to the subject of jurisprudence. But the Lord had other work for Luther: grace was already working in his heart. He was about that time given to much prayer; and used to say, "that prayer is the better half of studying"—a good maxim for all christian students.