Hadith 587
Narrated Muawiya: You offer a prayer which I did not see being offered by Allah's Apostle when we were in his company and he certainly had forbidden it (i.e. two rak`at after the `Asr prayer).
Hadith 696
Narrated Anas bin Malik: The Prophet said to Abu-Dhar, "Listen and obey (your chief) even if he is an Ethiopian with a head like a raisin."