Chapter on the traveler saying takbir when he ascends heights and the like, and saying tasbih when he descends into valleys and the like

The reader: Praise be to Allah, Lord of the worlds, and may prayers and peace be upon our Prophet Muhammad, and upon his family and all his Companions:
He said -may Allah have mercy on him-: "Chapter on the traveler saying takbir when he ascends heights and the like, and saying tasbih when he descends into valleys and the like, and the prohibition of exaggeration by raising the voice in takbir and the like:
Jabir (may Allah be pleased with him) said:

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."

كنا إذا صعدنا كبرنا، وإذا نزلنا سبحنا

Sahih al-Bukhari 2993

Al-Bukhari narrated it.
And Ibn 'Umar (may Allah be pleased with them both) said:

The Prophet (ﷺ) and his armies said: "Allah is Most Great" when they went up to high ground; and when armies said: "Allah is most Great" when they went up to high ground; and when they descended, they said: "Glory be to Allah."

كان النبي صلى الله عليه وسلم وجيوشه إذا عَلَوا الثنايا كبروا، وإذا هبطوا سبَّحوا

Sunan Abi Dawud 2599

Abu Dawud narrated it with a sound chain".

The Shaykh : In the name of Allah, the Most Gracious, the Most Merciful:
This chapter was established by the author al-Nawawi -may Allah have mercy on him- in *Riyad al-Salihin* under the etiquettes of travel and what is said therein:
Among these is that it is one of the etiquettes of travel: when a person ascends something high, such as a mountain, and likewise when an airplane ascends, he says takbir, saying: Allahu Akbar, either once, twice, or three times. And when he descends, he says tasbih, saying: Subhan Allah, once, twice, or three times. The reason for this is that when a person ascends, he sees himself in a high place, so he may become arrogant and say: Allahu Akbar, meaning he returns himself to humility before the majesty of Allah (Mighty and Majestic), saying: Allahu Akbar, meaning if you, O soul, have ascended, then above you is One who is higher than you, and He is Allah (Exalted and Majestic is He). So he says: Allahu Akbar. But when he descends, descending is lowering, nearness, humility, and submission, so he says: Subhan Allah, meaning I purify Allah (Glorified and Exalted is He) from lowering and descending, for He (Glorified and Exalted is He) is above everything. And although it is established from His Messenger (peace and blessings be upon him and his family): : This is a descent befitting His majesty and greatness, and it does not imply lowering, for Allah the Exalted is not like anything else. So the important point is that these are recommended etiquettes from the guidance of the Messenger (peace and blessings be upon him) and his Companions: when you ascend, you say: Allahu Akbar, and when you descend into a valley, you say: Subhan Allah. Likewise, the airplane says takbir when it ascends, and says tasbih when it descends at the airport, because there is no difference between ascending in the air and descending from it or onto the ground. And success is from Allah.