Surah 25. Al-Furqan, Ayah 48

Cf. vii. 57. The Winds are heralds of Joy, ushering in Rain, which is one form of Allah's Mercy. Again, the symbolism presents a fresh point of view. Heat (which is connected with light) sets up currents in the atmosphere, besides sucking up moisture from the seas, and distributing it by means of Winds over wide surfaces of the earth. In the physical world we know the beneficent action of heat on life, and by contrast, we also know how intolerable high temperatures may become, and how the cloud-bearing Winds come as welcome heralds of rain.

Rain water (in pure air) is not only pure water distilled in air and sky, but it is the best purifying and sanitating agent on the largest scale known to US.