Riyad as-Salihin, Book 8, Hadith 976 (In-Book) ⓘ
Ibn 'Umar (May Allah be pleased with them) reported: Whenever the Prophet and his army ascended a height, they would proclaim: "Allahu Akbar (Allah is Greatest)," and when they climbed down, they would proclaim: "Subhan Allah (Allah is free from imperfection)."[Abu Dawud].
وعن ابن عمر رضي الله عنهما قال: كان النبي صلى الله عليه وسلم وجيوشه إذا علو الثنايا كبروا، وإذا هبطوا سبحوا. ((رواه أبو داود بإسناد صحيح.