Musnad Ahmad 5:475

'Abd al-Rahman narrated to us, Shu'bah narrated to us, from 'Amr ibn Murrah, from Abu al-Bakhtari, from Abu 'Abd al-Rahman al-Sulami, who said: 'Ali said: "When I narrate to you a hadith from the Messenger of Allah, may Allah bless him and grant him peace, then think of the Messenger of Allah, may Allah bless him and grant him peace, as the most guided, the most rightly guided, and the most God-fearing of them."