The Messenger of Allah ﷺ said, "The best of horses is one that is jet black, with a white blaze on the forehead, white markings on the legs, a white upper lip, and a free right foreleg without white markings. If not jet black, then a dark bay with these same markings."
حدثنا محمد بن بشار حدثنا وهب بن جرير حدثنا أبي قال سمعت يحيى بن أيوب يحدث عن يزيد بن أبي حبيب عن علي بن رباح
أن رسول الله ﷺ قال خير الخيل الأدهم الأقرح المحجل الأرثم طلق اليد اليمنى فإن لم يكن أدهم فكميت على هذه الشية
[Its chain of transmission is hasan] Tirmidhi narrated it in jihad, chapter on what is recommended regarding horses, no. 1697, from Muhammad bin Bashshar through this route, and Tirmidhi said, hasan, gharib, sahih. Ibn Hibban graded it sahih, no. 1633, as did Hakim, 2/92, and Dhahabi. It has other paths of transmission as well.