His Kindness to the wrongdoers
He once found out that an ewe had a broken leg. He called one of his slaves and asked him: "Who did it?"
"I," the slave answered.
"Why?"
"So as to disconcert you!" the slave retorted.
The Imam [a] smiled to him and said: "But I will make you happy."
He freed him and generously rewarded him.
A Syrian, imbued with hatred and spite against the family of the Messenger of Allah [s], by Mu'awiyah bin Abu Sufyan, once saw the Imam on horseback. He at once emitted a series of curses! Imam Hasan [a] did not put in a word of protest or interruption. When the man finished, Imam Hasan [a] approached him with a tender smile. He said to him:
"O old man! I think you are a stranger here. Maybe you mistook me for someone else? If you propitiate us, we will satisfy you. If you ask us, we will give you what you need. If you ask our advice, we will guide you. If you ask us to give you a ride, we will take you with us. If you are hungry, we will satisfy you. If you are naked, we will clothe you. If you are in need, we will make you rich. It you are a refugee, we will give you lodgings. If you have a request, we will grant it. If you join your luggage to ours, and be our guest until the time of your travel, it will be more useful to you, because we have a spacious place, a good social position, and a vast amount of money."
Upon hearing these words, the Syrian broke into tears. Then he said: "I bear witness that you are the viceroy of Allah on the earth. Allah knows best whom to entrust with His message. You and your father were the most hateful creatures of Allah to me. But now you and your father are the most beloved from among all the creatures of Allah to me."
http://www.al-islam.org/gallery/kids/Books/2ndimam/index.htm