By word and example Francis taught his disciples to be especially humble towards the clergy. "If ye be sons of peace," he often said, "ye shall win both clergy and people, and this is more acceptable to God than to win the people only and to scandalise the clergy. Cover their backslidings and supply their many defects, and when ye have done this be ye the more humble." He had to struggle against much opposition among the bishops, who looked upon him and his friars as intruders encroaching upon their rights. People had often advised him to obtain a Bull from Rome, to enable him to preach without asking permission, but it was through the power of persistent meekness that he wished to win his way to every heart, and the only weapons he used were those of love. St. Bonaventura tells us that the Bishop of Imola absolutely refused to let Francis call the citizens together and preach to them. "It suffices, friar, that I preach to the people myself," was the cross reply, and Francis, drawing his cowl over his head, humbly went his way. But after the short space of an hour he retraced his steps, and the bishop inquired with some anger why he had returned. He made answer in all humility of heart and speech: "My lord, if a father sends his son out at one door there is nothing left for him but to return by another." Then the bishop, vanquished by his humility, embraced him with a joyful countenance, saying: "Thou and all thy brethren shall have a general licence to preach throughout my diocese, as the reward of thy holy humility."[40]