Rejoice, o City of Cologne, which one day received within your walls John Duns Scotus, a very intelligent and pious man, who, on November 8, 1308, passed from the present life to the heavenly fatherland; and you, with great admiration and veneration, preserve his remains....Confirmed in his Catholic faith, he made an effort to understand, explain, and defend the truth of faith in the light of human reason. Therefore, he made nothing other than demonstrating the knowledge of all truth, natural and supernatural, which come from the same and only Source.Along with Holy Scripture, divinely inspired, stands the authority of the Church. He follows the words of Saint Augustine: "I would not believe in the Gospel, if first I did not believe in the Church." In fact, our Doctor places in an elevated position, the supreme authority of the Successor of Peter. According to his words, "although the Pope cannot establish against natural and divine law (because his power is inferior to both), nevertheless, being the Successor of Peter, the Prince of the Apostles, he has the same authority that Peter had."Therefore, the Catholic Church, which has as its invisible Head Christ himself, who left his Vicars in the person of blessed Peter and of his Successors, guided by the Spirit of truth, is the authentic guardian of the revealed Deposit and of the rule of faith. The Church is the firm and stable criterion of the canonicity of Holy Scripture. She, in fact, "established what books should be considered authentic in the canon of the Bible".He elsewhere affirms that "the Scriptures have been explained with that same Spirit with which they were written, and it must thus be believed that the Catholic Church has presented them with that same Spirit with which the Faith was delivered to us, that is, instructed by the Spirit of truth."After having proved with various arguments, brought forth by theological reason, the very fact of the preservation of the Blessed Virgin Mary from original sin, he was nevertheless absolutely ready even to reject his understanding, it it were not in harmony with the authority of the Church, declaring: "If it does not disagree with the authority of the Church or with the authority of Scripture, it seems probable to attribute to Mary that which is most excellent".