And We placed within the earth firmly set mountains, lest it should (21:31)

Almuntakhab Fi Tafsir Alquran Alkarim

And We furnished the earth with firm stays Mountains* placed in a certain setting, fixed as with an anchor, to stabilize it lest it should sway you from side to side or in all directions and We furnished it with paths, roads, channels, routes by land and water and between mountains so that they may be guided in their journeys between the different places

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(21:31) And We set mountains firmly in the earth lest it should tilt to one side along with them *30 , and We left therein open paths *31 so that they may find their way. *32

And We placed within the earth firmly set mountains, lest it should meaning

*30) For explanation, see E. N. 12 of An-Nahl (XVI).
*31) "Open paths" are the passes between high mountains and the valleys and ravines made by the rivers in the mountainous regions and other natural ways that connect different regions on the earth.
*32) This is a very meaningful sentence. It may mean that the people may find paths for travelling on the earth, and it may also mean that the wisdom that underlies the skill and the system of their creation may guide them to the Reality.
 

And We placed within the earth firmly set mountains, lest it should meaning in Urdu

اور ہم نے زمین میں پہاڑ جما دیے تاکہ وہ انہیں لے کر ڈھلک نہ جائے اور اس میں کشادہ راہیں بنا دیں، شاید کہ لوگ اپنا راستہ معلوم کر لیں