Narrated Jabir bin `Abdullah: Whenever we went up a place we would say, "Allahu--Akbar (i.e. Allah is Greater)", and whenever we went down a place we would say, "Subhan Allah."
Hadith Referenceصحيح البخاري / كتاب الجهاد والسير / 2993
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة