Sahih Bukhari
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
Volume: 005 / Book Number: 059 / Hadith Number: 673
Narrated Abu Huraira:
The Prophet said, "The people of Yemen have come to you, and they are more soft hearted and gentle hearted people. The capacity for understanding religion is Yemenite and Wisdom is Yemenite."