Abu Dawud Book 36, Hadith Number 4867.
Chapter : Not known.
Narated By Jundub : A desert Arab came and making his camel kneel and tethering it, entered the mosque and prayed behind the Apostle of Allah (PBUH). When The Apostle of Allah (PBUH) had given the salutation, he went to his riding beast and, after untethering and riding it, he called out: O Allah, show mercy to me and to Muhammad and associate no one else in Thy mercy to us. The Apostle of Allah (PBUH) then said: Do you think that he or his camel is farther astray? Did you not listen to what he said? They replied: Certainly.