Ар-Рад 13:17

He then strikes a similitude of truth and falsehood, saying: He, exalted be He, sends down water, rain, from the sky, whereat the valleys flow according to their measure, according to their full capacity, and the flood carries a scum that swells, rising above it, and this [scum] is the filth and the like that lies on the surface of the earth, and from that which they smelt (read tūqidūn, ‘you smelt’, or yūqidūn, ‘they smelt’) in the fire, of the earth’s minerals, such as gold, silver or copper, desiring, seeking [to make], ornaments, adornment, or ware, which is useful, such as utensils, when they [the minerals] are melted; [there rises] a scum the like of it, that is, the like of the scum of the flood, and this [latter scum] consists of the impurities expelled by the bellows. Thus, in the way mentioned, God points out truth and falsehood, that is, [He points out] the similitude thereof. As for the scum, of the flood and of the minerals smelted, it passes away as dross, useless refuse, while that which is of use to mankind, in the way of water and minerals, lingers, remains, in the earth, for a time: likewise, falsehood wanes and is [eventually] effaced, even if it should prevail over the truth at certain times. Truth, on the other hand, is established and enduring. Thus, in the way mentioned, God strikes, He makes clear, similitudes.