Musnad Ahmad 33:1159

Abdullah ibn Muhammad narrated to us, Yahya ibn Zakariya ibn Abi Za'idah narrated to us, from Ibn Jurayj, from 'Ata', from Jabir, that the Prophet, peace and blessings of Allah be upon him, said to him: "I have taken your camel for four dinars, and you have its back [the right to ride it] until Medina."