It is narrated from Hazrat Abu Musa (may Allah be pleased with him) that a man came to him while he was eating chicken. That man sat to one side and said, "I have sworn an oath that I will not eat it because I see chickens eating filth." He (Abu Musa) said, "Come closer, for I will tell you about this. Once, I was with a group of Ash'aris in the service of the Noble Prophet (peace and blessings be upon him). We requested riding animals from the Noble Prophet (peace and blessings be upon him), so he said, 'By Allah! I cannot mount you, for I have nothing to mount you on.' We waited for a while, as long as Allah willed, then the Noble Prophet (peace and blessings be upon him) ordered for three camels with bright foreheads for us. When we were about to leave, one of us said to another, 'We came to the Noble Prophet (peace and blessings be upon him) to request riding animals, and he swore an oath that he would not give us riding animals. Let us go back and remind the Noble Prophet (peace and blessings be upon him) of his oath.' So we again presented ourselves before the Noble Prophet (peace and blessings be upon him) and said, 'O Messenger of Allah (peace and blessings be upon him)! We came to you to request riding animals, and you swore an oath that you would not give us riding animals, yet you gave us animals?' The Noble Prophet (peace and blessings be upon him) said, 'I did not mount you, but Allah did. By Allah! If Allah wills, whenever I swear an oath and see something better in another matter, I will choose that and offer expiation for my oath.'" The previous hadith is also narrated through this second chain.