St. Aidan of Lindisfarne, Bishop
Aidan lived not as a prince bishop but as a simple monk, with an austerity difficult for us to imagine. He gave away almost every gift he was given, simply because someone else needed it, and he insisted that others -- including King Oswald -- be just as generous. As Aidan grew older and found traveling on foot more difficult, Oswald gave him a horse from the royal stables.
Aidan was overjoyed, and rode out on his journey. A half mile down the road he saw a beggar and gave him the horse, elaborate saddle and bridle included, and then continued on foot. When Aidan returned, Oswald was furious, asking, "Why that particular horse? Couldn't you at least have asked for an ordinary horse to give the man?" Aidan retorted, "Do you care for for the child of a mare than for a child of God?" Oswald cast off his sword and knelt in repentance.
For more information on St. Aidan, see the article here.