The king of Aylah gifted the Prophet ﷺ a white mule, clothed him with a cloak, and wrote him a guarantee concerning their sea territory.
أهدى ملك أيلة للنبي ﷺ بغلة بيضاء، وكساه بردا، وكتب له ببحرهم.
Bukhari related it in the Book of Zakat (1481), and Muslim in the Book of Virtues (11/1392), both from the hadith of Amr bin Yahya, from Abbas bin Sahl bin Saad Saadi, from Abu Humayd Saadi, who mentioned it in a long hadith, and the wording given here is that of Bukhari.