Sunan an-Nasa'i, Hadith 1438 ⓘ
It was narrated that Anas said: "I went out with the Messenger of Allah from Al-Madinah to Mekkah, and he continued to shorten his prayers, and he stayed there for ten days."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ يَحْيَى بْنِ أَبِي إِسْحَاقَ، عَنْ أَنَسٍ، قَالَ خَرَجْتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم مِنَ الْمَدِينَةِ إِلَى مَكَّةَ فَلَمْ يَزَلْ يَقْصُرُ حَتَّى رَجَعَ فَأَقَامَ بِهَا عَشْرًا .
also referenced under: Book 15, Hadith 6 (In-Book) & Volume 2, Book 15, Hadith 1439 (DarusSalam)