Musnad Ahmad 1017:33

Yahya ibn Sa'id narrated to us, 'Abd al-Jalil narrated to us, he said: I arrived at a circle in which were Abu Mijlaz and the two sons of Buraydah. 'Abdullah ibn Buraydah said: My father, Buraydah, narrated to me, he said: I hated 'Ali with a hatred I had never felt for anyone before. And I loved a man from Quraysh, and I did not love him except for his hatred of 'Ali. He said: That man was sent in command of a cavalry, so I accompanied him, and I did not accompany him except for his hatred of 'Ali. He said: We captured some captives. He said: So he wrote to the Messenger of Allah (may Allah bless him and grant him peace), "Send us someone to divide the fifth." He said: So he sent 'Ali to us. Among the captives was a slave girl who was the best of the captives. He divided the fifth and distributed [the rest]. Then he came out, and his head was dripping [with water]. We said: "O Abu al-Hasan, what is this?" He said: "Did you not see the slave girl who was among the captives? I divided and took the fifth, and she became part of the fifth. Then she became part of the household of the Prophet (may Allah bless him and grant him peace), then she became part of the family of 'Ali, and I had intercourse with her." He said: The man wrote to the Prophet of Allah (may Allah bless him and grant him peace), and I said: "Send me." So he sent me as a messenger. He said: I began to read the letter and say: "He has spoken the truth." He said: He took my hand and the letter and said: "Do you hate 'Ali?" He said: I said: "Yes." He said: "Do not hate him, and if you love him, then increase in love for him. For by the One in Whose hand is the soul of Muhammad, the share of the family of 'Ali in the fifth is better than a slave girl." He said: There was no one among the people after the words of the Messenger of Allah (may Allah bless him and grant him peace) more beloved to me than 'Ali. 'Abdullah said: By the One besides Whom there is no god, there is no one between me and the Prophet (may Allah bless him and grant him peace) in this hadith except my father, Buraydah.