Musnad Ahmad 30:3153

Narrated to us Abd al-Rahman, from Zuhayr, from al-Ala’, from his father, from Abu Hurayrah, from the Prophet, may Allah bless him and grant him peace, who said: "Faith is Yemeni, and disbelief is toward the east. Tranquility is in the people of sheep, and pride and showing off are in the loud-voiced ones, the people of horses and the people of camel-hair tents."