This is taken from perhaps the greatest life of Saint Francis of Assisi, by Saint Bonaventure, who drew on people who actually knew Saint Francis.
“The Son of God, Saint Francis used to say, descended from the sublimity of the Father’s bosom to share our misery and become our Lord and Teacher, in order to teach us humility by word and example. Therefore, as Christ’s true disciple, he was careful to preserve a low opinion of himself… Consequently he was convinced that it was foolish to be elated when people showed him marks of respect: he was upset when praised, but overjoyed when he was insulted. He liked to have people scorn him–that spurred him on to do better–and hated to be praised, which could lead to a fall. When people praised the height of his sanctity, he used to command one of the friars to do the opposite and heap insults on him…
Because Francis preferred humility in himself and in his friars to any earthly honor, God who loves the humble judged him worthy of the highest honor. This was revealed to one of the friars, a virtuous and holy men, in a vision which he had from heaven. He was traveling with St. Francis when they went into an abandoned church, where they prayed fervently. There this friar was in an ecstasy and saw a vision of a multitude of thrones in heaven, one of which was radiant with glory and adorned with precious stones and ranked higher than the rest. He marveled at its splendor and fell to wondering whose it was going to be. Then he heard a voice telling him, “That throne belonged to one of the fallen angels. Now it is being kept for the humble Francis.” When the friar came back to himself, he followed the saint out of the church as usual. As they continued on their journey conversing together about God, the friar remembered his vision and discreetly asked the saint what he thought of himself. “It seems to me,” Francis replied, “that I must be the greatest of all sinners.” When his companion reproached him, declaring that he could not possibly say that with a good conscience, or really believe it, Francis continued, “If Christ had shown such mercy towards the greatest criminal in the world, I am convinced that he would be much more grateful to God than I am.” At the sight of such extraordinary humility, his companion was convinced of the truth of his vision: he knew from the testimony of the Gospel that the truly humble person is exalted to the height of glory from which the proud man is excluded.”
(from St. Bonaventure’s “Major Life of St. Francis” in “St. Francis of Assisi; Writings and Early Biographies, English Omnibus of Sources,” ed. Marion A. Habig [Chicago: Franciscan Herald Press, 1983], pp. 671, 675-6)