Musannaf Ibn Abi Shayba 28:911

Waki’ narrated to us, from Shu’bah, from Ghalib al-‘Abdi, who said: A man from Banu Numayr narrated to me, from his father, from his grandfather—or his great-grandfather—that he came to the Prophet, may Allah bless him and grant him peace, and said: "O Messenger of Allah, my people have accepted Islam on the condition that I provide them with such and such." He said: "If you wish, you may take it back, but leaving it is better."