Musannaf Ibn Abi Shayba 13:2008

Abu Bakr narrated to us, he said: Ya'la ibn 'Ubayd narrated to us, from al-Harith ibn 'Umayr, from Yahya ibn Sa'id, he said: When the Prophet, may Allah bless him and grant him peace, sent Ibn Rawaha to the people of Khaybar, they gifted him a fur garment. He said: "It is unlawful gain (suht)."