Musnad Ahmad 748:1

Hisham ibn Sa’id narrated to us, Muhammad ibn Muhajir—meaning the brother of ‘Amr ibn Muhajir—narrated to us, he said: ‘Aqil ibn Shabib narrated to me, from Abu Wahb al-Jushami, and he had companionship [with the Prophet], he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Name yourselves with the names of the prophets. The most beloved names to Allah the Almighty are ‘Abdullah and ‘Abdur-Rahman. The most truthful of them are Harith and Hammam. The ugliest of them are Harb and Murrah. Tie up horses, and wipe their forelocks and their rumps—or he said: their haunches—and put garlands on them, but do not put bowstrings on them as garlands. And upon you is every dark bay horse with a white blaze and white feet, or a reddish-bay horse with a white blaze and white feet, or a black horse with a white blaze and white feet."