Musnad Ahmad 937:261

Yazid narrated to us, Kahmas ibn al-Hasan narrated to us, Abu al-Sulayl narrated to us, from Abu Dharr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) began to recite this verse to me: "And whoever fears Allah, He will make for him a way out" [At-Talaq: 2], until he finished the verse. Then he said: "O Abu Dharr, if all the people were to take hold of it, it would suffice them." He said: So he kept reciting it and repeating it to me until I became drowsy. Then he said: "O Abu Dharr, what will you do if you are driven out of Medina?" I said: I will go to ease and comfort; I will go until I am a pigeon among the pigeons of Mecca. He said: "What will you do if you are driven out of Mecca?" I said: I will go to ease and comfort, to Ash-Sham and the Holy Land. He said: "What will you do if you are driven out of Ash-Sham?" I said: Then, by the One who sent you with the truth, I will place my sword upon my shoulder. He said: "Or [shall I show you] what is better than that?" I said: Or what is better than that? He said: "You listen and obey, even if it is an Abyssinian slave."