Sahih Bukhari Volume 8, Book 73, Hadith Number 39.

Narated By Abu Huraira : Allah’s Apostle stood up for the prayer and we too stood up along with him. Then a Bedouin shouted while offering prayer. “O Allah! Bestow Your Mercy on me and Muhammad only and do not bestow it on anybody else along with us.” When the Prophet had finished his prayer with Taslim, he said to the Bedouin, “You have limited (narrowed) a very vast (thing),” meaning Allah’s Mercy.