Sunan Abi Dawud Book 15, Hadith 67
The Messenger of Allah (ﷺ) said: Keep to every dark bay horse with a white blaze and white on the legs, or sorrel with a white blaze and white on the legs , or black with a white blaze and white on the legs.
Utbah heard the Messenger of Allah (ﷺ) say: Do not cut the forelocks, manes, or tails of horse, for their tails are their means of driving flies, their manes provide them with warmth, and blessing is tide to their forelocks.
The Prophet (ﷺ) said: Keep to every sorrel horse with a white blaze and white on the legs, or dark bay with a white blaze. He then mentioned something similar. Muhammad ibn al-Muhajir said: I asked him: Why was a sorrel horse preferred? He replied: Because the Prophet (ﷺ) had sent a contingent, and the man who first brought the news of victory was the rider of a sorrel horse.