St. Bonaventure, Itinerarium mentis in Deum 7.6, as translated in the Liturgy of the hours, Office of readings for the Feast of St. Bonaventure. Latin from p. 313 of vol. 5 of the Quaracchi edition as reproduced in Itinerarium mentis in Deum, trans. Zachary Hayes, Works of St. Bonaventure (Saint Bonaventure, NY: Franciscan Institute Publications, 2002), 138. (The translation in the heading, however, is taken from the one by Hayes.)
Yet this comes, of course, at the end of a long and rigorous itinerarium. "For Saint Bonaventure is an intellectual, although not an intellectualist; his vocation is that of a theologian who craves for understanding. Intellectual activity is as necessary for him [(as distinguished from his master, Saint Francis of Assisi)] as his daily bread" (Philotheus Boehner, OFM, in the "Notes and commentary" (p. 220 of the Franciscan Institute edition given above)).