Surah 16. An-Nahl, Ayah 15

This is apparently an allusion to the fact that the mountains owe their rise to the gradual balancing process to which the solid crust of the earth is subject - a process which, in its turn, is the result of stresses and disturbances due to the cooling and hardening, progressing from the surface towards the centre, of the presumably molten or perhaps even gaseous matter of which the earth's interior seems to be composed. It appears that part of this interior is kept solid only by the enormous pressure of the overlaying material, of which the mountains are the most vivid evidence: and this explains the Qur'anic reference (in 78:7 ) to mountains as "pegs" (awtad), i.e. symbols of the firmness and relative equilibrium which the surface of the earth has gradually achieved in the course of its geological history. Notwithstanding the fact that this equilibrium is not absolute (as is evidenced by earthquakes and volcanic eruptions), it is the solidity of the earth's crust - as contrasted with its possibly fluid but certainly very unstable interior - which makes life on earth possible: and this, to my mind, is the meaning of the phrase "lest it sway with you" (or "with them") occurring in the above verse as well as in 21:31 and 31:10 .

Cf. xiii. 3 and xv. 19. Here and elsewhere the earth is spoken of as a spacious carpet beneath our feet and the hills as a steadying agent to keep the carpet from rolling or shaking about. In lxxvii. 7 they are spoken of as pegs or stakes.

In this passage (xvi. 15-16) we have the metaphor of the fixed mountains further allegorised. In these verses the key-words are indicated by the symbols for man's Guidance (tahtadun). First, the physical symbols are indicated; the mountains that stand firm and do not change from day to day in the landscape, unlike shifting sand-dunes, or the coast line of the sea, or rivers and streams, which frequently change their courses, then we have rivers and roads, which are more precise and therefore more useful, though less permanent; then we have 'alamat (sign-posts), any kinds of signs erected by man, like direction posts, light-houses or beacons, or provided in nature, as tall trees, etc.; and finally, we have the pole-star, and now the magnetic needle, with its variations marked on navigation charts. All these are symbols for the higher Guidance which Allah provides for the spirit of man. See next note.