Musnad Ahmad 32:1426

Yunus and Surayj narrated to us, they said: Hammad—meaning Ibn Zayd—narrated to us, from Thabit, from Anas, that the Prophet, peace and blessings of Allah be upon him, saw a trace of yellow (saffron) on Abd al-Rahman ibn Awf and said: "What is this?" He said: "I have married a woman for the weight of a date stone of gold." He said: "May Allah bless you. Give a wedding feast, even if with a sheep."