The Messenger of Allah ﷺ said, "The people of Yemen have come to you. They are the most tender-hearted. Faith is Yemeni, wisdom is Yemeni, and understanding of religion is Yemeni."
حدثنا محمد بن أبي عدي عن ابن عون عن محمد
قال رسول الله ﷺ أتاكم أهل اليمن هم أرق أفئدة الإيمان يمان والحكمة يمانية والفقه يمان
Its chain of transmission is sahih. Muslim reported it, 1:30, via the route of Ibn Adi and Ishaq Azraq, both from Ibn Awn from Ibn Sirin, and he referred its wording to the narration before it, via the route of Hammad bin Zayd from Ayub from Ibn Sirin. He then reported it with similar wording through various different chains. Bukhari reported it, 7, and Tirmidhi, 4:377-378, through other chains.The letter waw in his statement "and understanding" was dropped in H, which is a printing error. We have restored it from K and M.As for his statement "yaman and yamaniyah," these are with fatha on the ya and a light mim, and with a light final ya in the second word. In Lisan, 17:357, it says, their saying "a yaman man" is attributed to Yemen. The original was "yamani," but they added an alif and dropped the ya of attribution. Likewise their saying "a sham man" was originally "shami," and they added an alif and dropped the ya of attribution. And Tihamah was originally "tihamah," and they added an alif, and said "tihami." Azhari said, this is the view of Khalil and Sibawayh.Jawhari said, Yemen is a land of the Arabs, and the attribution to it is "yamani" and "yaman" with the mim lightened, and the alif substitutes for the ya of attribution, so the two cannot occur together. Sibawayh said, some say "yamani" with the doubled letter.