Sunan an-Nasa'i, hadith 1635

أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا مُعْتَمِرٌ، عَنْ أَبِيهِ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم لَيْلَةَ أُسْرِيَ بِهِ مَرَّ عَلَى مُوسَى عَلَيْهِ السَّلاَمُ وَهُوَ يُصَلِّي فِي قَبْرِهِ ‏.‏

It was narrated from Anas that:On the night on which he was taken on the Night Journey, the Prophet (ﷺ) passed by Musa, peace be upon him, and he was praying in his grave