he sends down water from the sky whereat the valleys are flooded to their capacity and the flood carries along a swelling scum. and from what they smelt in the fire for the purpose of ornaments or wares a similar scum. that is how allah compares truth and falsehood. as for the scum it leaves as dross and that which profits the people stays in the earth. that is how allah draws comparisons.
أنزل من السماء ماء فسالت أودية بقدرها فاحتمل السيل زبدا رابيا ومما يوقدون عليه في النار ابتغاء حلية أو متاع زبد مثله كذلك يضرب الله الحق والباطل فأما الزبد فيذهب جفاء وأما ما ينفع الناس فيمكث في الأرض كذلك يضرب الله الأمثال