Why did the Prophet Muhammad (saw) respond differently when the people of Banu Tamim asked for material things compared to when the people from Yemen asked for good tidings?
 Narrated `Imran bin Husain:                     The people of Banu Tamim came to Allah's Apostle, and he said, "Be glad (i.e. have good tidings). O Banu Tamim!" They said, "As you have given us good tidings then give us (some material things)." On that the features of Allah's Apostle changed (i.e. he took it ill). Then some people from Yemen came, and the Prophet said (to them) "Accept good tidings as Banu Tamim have not accepted them." They said, "We accept them, O Allah's Apostle!"