Quran 13:17 Ar-Ra'd, ayah 17 of 43

أَنزَلَ مِنَ ٱلسَّمَآءِ مَآءً فَسَالَتْ أَوْدِيَةٌۢ بِقَدَرِهَا فَٱحْتَمَلَ ٱلسَّيْلُ زَبَدًا رَّابِيًا ۚ وَمِمَّا يُوقِدُونَ عَلَيْهِ فِى ٱلنَّارِ ٱبْتِغَآءَ حِلْيَةٍ أَوْ مَتَـٰعٍ زَبَدٌ مِّثْلُهُۥ ۚ كَذَٰلِكَ يَضْرِبُ ٱللَّهُ ٱلْحَقَّ وَٱلْبَـٰطِلَ ۚ فَأَمَّا ٱلزَّبَدُ فَيَذْهَبُ جُفَآءً ۖ وَأَمَّا مَا يَنفَعُ ٱلنَّاسَ فَيَمْكُثُ فِى ٱلْأَرْضِ ۚ كَذَٰلِكَ يَضْرِبُ ٱللَّهُ ٱلْأَمْثَالَ ۝١٧

13:17 He sendeth down water from the sky, so that valleys flow according to their measure, and the flood beareth (on its surface) swelling foam - from that which they smelt in the fire in order to make ornaments and tools riseth a foam like unto it - thus Allah coineth (the similitude of) the true and the false. Then, as for the foam, it passeth away as scum upon the banks, while, as for that which is of use to mankind, it remaineth in the earth. Thus Allah coineth the similitudes.