52:44
وَ إِن يَرَ وْا۟ كِسْفًا مِّنَ ٱل سَّمَآءِ سَاقِطًا يَقُولُ وا۟ سَحَابٌ مَّرْكُومٌ
And if they were to see a fragment from the sky falling, they would say, "[It is merely] clouds heaped up."
8:37
لِ يَمِيزَ ٱللَّهُ ٱلْ خَبِيثَ مِنَ ٱل طَّيِّبِ وَ يَجْعَلَ ٱلْ خَبِيثَ بَعْضَ هُۥ عَلَىٰ بَعْضٍ فَ يَرْكُمَ هُۥ جَمِيعًا فَ يَجْعَلَ هُۥ فِى جَهَنَّمَ أُو۟لَٰٓئِكَ هُمُ ٱلْ خَٰسِرُونَ
[This is] so that Allah may distinguish the wicked from the good and place the wicked some of them upon others and heap them all together and put them into Hell. It is those who are the losers.