Musannaf Ibn Abi Shayba 21:662

Abu al-Ahwas narrated to us, from Mansur, from Abdullah, from Abd al-Rahman ibn Abza, who said: Ali used to say in the prayer over the deceased: "O Allah, forgive our living and our dead, and reconcile our hearts, and rectify the matters between us, and place our hearts upon the hearts of our best ones. O Allah, forgive him. O Allah, have mercy upon him. O Allah, return him to something better than what he was in. O Allah, [grant us] Your pardon."