The Life of St. Bonaventure of Bagnoregio

There was in St. Bonaventure something preeminent and unique, so that he stood out not only in subtlety of arguing, in facility of teaching, in cleverness of defining, but he excelled in a certain divine strength of thoroughly stirring up souls. For in writing with the greatest erudition he so conjoined an equal ardor of piety, that he would move the reader by teaching and it would sink into the recesses of the soul, and then he would prick the heart with certain seraphic stings and it would pour forth with a wonderful sweetness of devotion; admiring which grace poured out upon his mouth and pen, Our precedessor the Pontiff Sixtus IV, had no doubts in saying, that the Holy Spirit seemed to have spoken in him.

… he burned up with such ardor of fraternal charity and slaved for his brothers with such a self-abasement (demissio) of christian humility, that there was acknowledged in him that saying of the Lord:

“Let him who is greater among you, be as your servant.” Matthew 20: 26

Triumphantis Jerusalem., Pope Sixtus V