From Tears to Inner Light
St. Francis had attained a wondrous purity of soul and body, yet he never stopped purifying the eyes of his spirit with a flood of tears, despite the fact that it was damaging his bodily sight. As a result of his continual weeping, he developed a serious eye disease. But when the doctor tried to persuade him to restrain his tears if he wanted to prevent blindness, St. Francis replied, “Brother Doctor, we shouldn’t, in order to preserve that light we share in common with the flies, refuse even the smallest measure of that eternal light which visits us. The gift of sight was not given to the spirit for the good of the body, but to the body for the good of the spirit.” He preferred to loose the light of his eyes rather than to dry up the fervor of his spirit by damming up his tears which cleansed his interior sight and rendered him able to see God.
-- St. Bonaventure, Major Life, 5:8