Sunan an-Nasai Book 21, Hadith 2039

أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ حَدَّثَنَا إِسْمَاعِيلُ، قَالَ حَدَّثَنَا شَرِيكٌ، - وَهُوَ ابْنُ أَبِي نَمِرٍ - عَنْ عَطَاءٍ، عَنْ عَائِشَةَ، قَالَتْ ‏:‏ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم كُلَّمَا كَانَتْ لَيْلَتُهَا مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم يَخْرُجُ فِي آخِرِ اللَّيْلِ إِلَى الْبَقِيعِ فَيَقُولُ ‏:‏ ‏ "‏ السَّلاَمُ عَلَيْكُمْ دَارَ قَوْمٍ مُؤْمِنِينَ، وَإِنَّا وَإِيَّاكُمْ مُتَوَاعِدُونَ غَدًا أَوْ مُوَاكِلُونَ، وَإِنَّا إِنْ شَاءَ اللَّهُ بِكُمْ لاَحِقُونَ، اللَّهُمَّ اغْفِرْ لأَهْلِ بَقِيعِ الْغَرْقَدِ ‏"‏ ‏.‏

It was narrated that 'Aishah said that:every time it was her night for the Messenger of Allah to stay with her, he would go out at the end of the night to Al-Baqi' and say: "As-salamu 'alaykum dara qawmin mu'minin, wa inna wa iyyakum mutawa'idun ghadan wa mutawakilun, wa inna in sha' Allahu bikum lahiqun. Allahummaghfir li ahli baqi'il gharaqad. (Peace be upon you, O abode of believing people. You and we used to remind one another about the Day of Resurrection and we are relying on one another (with regard to intercession and bearing witness). Soon we will join you, if Allah willing. O Allah, forgive the people of Baqi' Al-Charqad