Malik bin Isma'il, Abu Ghasan al-Nahdi مالك بن إسماعيل أبو غسان النهدي · Chapters on Virtues

that the Messenger of Allah (ﷺ) said: "Leadership is among the Quraish, and reasoning and judgment is among the Ansar, and the Adhan is among the Ethiopians, and the trust is among the Al-Azd." meaning Yemen.