Mukhtasar Muslim

Sayyiduna Anas bin Malik (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) was the most cheerful of all people. I had a brother who was called Abu Umair (from this it is known that it is permissible to use a kunyah for a young child or one who does not have a child). (I think Anas said that) he had been weaned. When the Messenger of Allah (peace and blessings be upon him) would come and see him, he would say, "O Abu Umair! Where is the Nughair?" (Nughair refers to a nightingale or a small bird), and the boy used to play with it.