Musnad Abu Ya'la al-Mawsili 3:273

Al-Hasan ibn 'Arafah narrated to us, Waki' ibn al-Jarrah narrated to us, Yunus ibn Abi Ishaq narrated to us, from al-Sha'bi, from 'Ali, who said: I was sitting with the Messenger of Allah (may Allah bless him and grant him peace), and Abu Bakr and 'Umar approached. The Messenger of Allah (may Allah bless him and grant him peace) said: "These two are the masters of the middle-aged men of the people of Paradise, from the first and the last, except for the Prophets and the Messengers." "O 'Ali, do not inform them."