When people laid siege to the house of caliph Uthman and prevented rations from him, Imam Ali (a.s) ordered Imams Hasan and Husayn (a.s) to carry water skins and some loaves of bread and deliver them to the besieged people. Thus when the young men reached there the people stopped them but with great valour they moved ahead. Someone said, “These people are not deserving of mercy.” The Imams (a.s) replied, “May be not in your opinion. But the affection for creatures that Allah has created in our hearts demands that we help them in their difficulty.”
The fact is that except for the Ahl ul-Bayt it is not possible for anyone to show affection for people in such circumstances. It was only their kind-heartedness that they dealt with affection with their most staunch enemies.
Reference :Akhlaq al-A’imma, Morals & Manners of the Holy Imams