Sunan Ibn Majah, Book 25, Hadith 3102 (In-Book) ⓘ
It was narrated that Ibn ‘Umar said: “If I go quickly between Safa and Marwah, that is because I saw the Messenger of Allah going quickly, and if I walk that is because I saw the Messenger of Allah walking, even though I am an old man.”
حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، وَعَمْرُو بْنُ عَبْدِ اللَّهِ، قَالاَ حَدَّثَنَا وَكِيعٌ، حَدَّثَنَا أَبِي، عَنْ عَطَاءِ بْنِ السَّائِبِ، عَنْ كَثِيرِ بْنِ جُمْهَانَ، عَنِ ابْنِ عُمَرَ، قَالَ إِنْ أَسْعَ بَيْنَ الصَّفَا وَالْمَرْوَةِ فَقَدْ رَأَيْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ يَسْعَى وَإِنْ أَمْشِ فَقَدْ رَأَيْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ يَمْشِي وَأَنَا شَيْخٌ كَبِيرٌ .
also referenced under: Hadith 2988 (Reference) & Volume 4, Book 25, Hadith 2988 (DarusSalam)