It is narrated from Sayyiduna Abu Qatadah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The best of horses are the black ones whose forehead and upper lip are white, with white on three legs and the right foreleg free (of white). If it is not black, then a kumayt with the same markings, that is, black tinged with red, or one whose tail and mane are black and the rest red."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12895