(When He made the slumber fall upon you) when He cast sleepiness upon you (as a reassurance) to you (from Him) from Allah against the enemy; and this is a favour from Allah towards you (and sent down water) rain (from the sky upon you, that thereby He might purify you) with rain from physical and minor and major ritual impurities, (and remove from you the fear of Satan) the whispering of Satan, (and make strong your hearts) and preserve your hearts with steadfastness (and firm) by means of the rain ((your) feet thereby) on the sand, i.e. He gathers the sand such that feet become firm on it.
