Sunan Abi Dawud 882
سنن أبي داود#882SahihAbu Hurairah said; The Messenger of Allah (May peace be upon him) got up for the prayer and we also stood up along with him. A Bedouin said said during prayer; O Allah, show mercy to me and to Muhammed and do not show mercy to anyone along with us. When the Messenger of Allah (May peace be upon him) uttered the salutation, he said to the Bedouin; you narrowed down a vast (thing). By this he meant the mercy of Allah
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih
In-book reference: 2:492