Musannaf Ibn Abi Shayba 13:2678

Abu Bakr narrated to us, he said: Waki' narrated to us, he said: Shu'bah narrated to us, from Ibn Abi Najih, from Mujahid, he said: Ali said: "The *'Umra* (life-gift) and the *Ruqba* (contingent gift) are the same."