An event that marked his life happened when he was when he was just a boy. Struck by a serious illness from which not even his father, a doctor, thought he would recover, his mother prayed for the intercession of St. Francis and he was healed.
Years later, while studying in Paris he joined the Franciscans, explaining his choice by saying that this order "recognized the action of Christ."
Benedict XVI quoted Bonaventure's words from a letter to a brother in the order, "I confess before God that the reason that made me love the life of Blessed Francis most is that it is alike to the beginnings and the growth of the Church ... the religion of Blessed Francis was not established by the prudence of men, but by Christ."
While completing a difficult course of study in the Theology College of the University of Paris, the Holy Father recalled, "he matured his own personal reflection and a spiritual sensibility of great value that, in the course of the following years, he knew how to transfuse into his works and sermons, in this way becoming one of the most important theologians in the history of the Church."
He started to teach Franciscan theology in Paris and it was at this time that he wrote on "evangelical perfection," showing how the mendicant orders followed the Gospel through their practices of vows of poverty, chastity and obedience.
This teaching, said Pope Benedict, is "always current: the Church is enlightened and beautified by the faithfulness to their vocation of these sons and daughters of hers, who not only put the evangelical precepts into practice but, by God's grace, are called to observe the evangelical counsels and thus bear witness - with their poor, chaste and obedient lifestyle - to the fact that the Gospel is a source of joy and perfection."