Ibn 'Umar (May Allah be pleased with them) reported:
Whenever the Prophet ﷺ 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 ﷺ وجيوشه إذا علو الثنايا كبروا، وإذا هبطوا سبحوا. ((رواه أبو داود بإسناد صحيح.