It was narrated from Abu Salamah that :

Abu Hurairah said: "The Messenger of Allah ﷺ stood up to pray and we stood up with him. A Bedouin said- while he was praying- 'O Allah, have mercy on me and Muhammad and do not have mercy on anyone else.' When the Messenger of Allah ﷺ said the Salam, he said to the Bedouin: 'You have limited something vast," meaning the mercy of Allah (Subhanahu-wa-Taala)."

أَخْبَرَنَا كَثِيرُ بْنُ عُبَيْدٍ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ حَرْبٍ، عَنِ الزُّبَيْدِيِّ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي سَلَمَةَ، أَنَّ أَبَا هُرَيْرَةَ، قَالَ قَامَ رَسُولُ اللَّهِ ﷺ إِلَى الصَّلاَةِ وَقُمْنَا مَعَهُ فَقَالَ أَعْرَابِيٌّ وَهُوَ فِي الصَّلاَةِ اللَّهُمَّ ارْحَمْنِي وَمُحَمَّدًا وَلاَ تَرْحَمْ مَعَنَا أَحَدًا . فَلَمَّا سَلَّمَ رَسُولُ اللَّهِ ﷺ قَالَ لِلأَعْرَابِيِّ " لَقَدْ تَحَجَّرْتَ وَاسِعًا " . يُرِيدُ رَحْمَةَ اللَّهِ عَزَّ وَجَلَّ .