Sunan an-Nasa'i, Hadith 1631 ⓘ
It was narrated from Anas bin Malik that: The Messenger of Allah said: "On the night on which I was taken on the Night Journey (Al-Isra') I came to Musa, peace be upon him, at the red dune, and he was standing, praying in his grave."
أَخْبَرَنَا مُحَمَّدُ بْنُ عَلِيِّ بْنِ حَرْبٍ، قَالَ حَدَّثَنَا مُعَاذُ بْنُ خَالِدٍ، قَالَ أَنْبَأَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ سُلَيْمَانَ التَّيْمِيِّ، عَنْ ثَابِتٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ أَتَيْتُ لَيْلَةَ أُسْرِيَ بِي عَلَى مُوسَى عَلَيْهِ السَّلاَمُ عِنْدَ الْكَثِيبِ الأَحْمَرِ وَهُوَ قَائِمٌ يُصَلِّي فِي قَبْرِهِ .
also referenced under: Book 20, Hadith 34 (In-Book) & Volume 2, Book 20, Hadith 1632 (DarusSalam)