St. Francis of Assisi was traveling in Lombardy and entered a church to pray. The pastor of this parish was causing scandal by living with a woman. A man ran up to the saint and said to him: "Tell me: if a priest maintains a concubine and thereby stains his hands, must we believe in his teaching and respect the sacraments he administers?" The saint was not taken in by the trap the heretic had set; in the presence of all the parishoners he went to the priest's house, knelt down before him and said: "I do not really know whether these hands are stained as the other man claims they are. In any case, I do know that even if they are, this in no way lessens the power and efficacy of the sacraments of God; those hands remain the channel whereby God's graces and blessings stream down on the people. That is why I kiss them out of respect for what they administer and out of respect for Him who delegated his authority to them." Francis prostrated himself before the priest, kissed his hands to the great embarrasment of the heretics and their sympathizers who were present.
Stephen of Bourbon, Dominican (1261)
Edit. Lecroy de la Marche, Anecdotes historiques,
Paris, 1877, p. 264; Lemmens, Testimonia
minora, pp 93-94