Urwah al-Bariqi (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him): "Goodness is tied to the forelocks of horses until the Day of Resurrection, that is, reward and spoils." These are the words of Abu Nu'aym's hadith; in al-Azraq's narration the words "reward and spoils" are not present.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18479