Musnad Ahmad 929:2

Ali ibn Ishaq narrated to us, Abdullah ibn al-Mubarak narrated to us, Asim al-Ahwal informed us, from Abu Uthman, Ubayy ibn Ka'b narrated to me, he said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "As for you, you shall have what you sought the reward for."