Sahih al-Bukhari 2993
Sahih al-Bukhari · Book 56: Fighting for the Cause of Allah (Jihaad) · Reciting Subhan Allah when going down a valley
Narrated Jabir bin `Abdullah:
حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ ، حَدَّثَنَا سُفْيَانُ ، عَنْ حُصَيْنِ بْنِ عَبْدِ الرَّحْمَنِ ، عَنْ سَالِمِ بْنِ أَبِي الْجَعْدِ ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ ـ رضى الله عنهما ـ قَالَ كُنَّا إِذَا صَعِدْنَا كَبَّرْنَا، وَإِذَا نَزَلْنَا سَبَّحْنَا.
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."