It is narrated from Hazrat Anas (may Allah be pleased with him) that once Hazrat Abu Musa Ash'ari (may Allah be pleased with him) asked the Prophet (peace and blessings be upon him) for an animal to ride. The Prophet (peace and blessings be upon him) was busy with some work at that time, so he said, "By Allah! I will not give you any ride." But when he (Abu Musa) turned to leave, he was called back and was granted a ride. He said, "O Messenger of Allah (peace and blessings be upon him)! You had sworn that you would not give me a ride?" The Prophet replied, "Now I swear that I will surely give you a ride."