Sahih Muslim 52 a
It is narrated on the authority of Abu Huraira that the Messenger of Allah observed:
There have come the people of Yemen; they are tender of hearts, the belief is that of the Yemenites, the understanding (of the faith) is that of the Yemenites and sagacity is that of the Yemenites.
حَدَّثَنَا أَبُو الرَّبِيعِ الزَّهْرَانِيُّ، أَنْبَأَنَا حَمَّادٌ، حَدَّثَنَا أَيُّوبُ، حَدَّثَنَا مُحَمَّدٌ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ جَاءَ أَهْلُ الْيَمَنِ هُمْ أَرَقُّ أَفْئِدَةً الإِيمَانُ يَمَانٍ وَالْفِقْهُ يَمَانٍ وَالْحِكْمَةُ يَمَانِيَةٌ ‏"‏ ‏.‏