﴿ وَلِيُمَحِّصَ ٱللَّهُ ٱلَّذِينَ ءَامَنُوا۟ وَيَمْحَقَ ٱلْكَٰفِرِينَ ﴾

“and that God might render pure of all dross those who have attained to faith, and bring to nought those who deny the truth.”

And that God may prove the believers and efface the disbelievers. The tests of the unseen are a kind of smelting for the servant. Through various stages He purifies him from faults so that he becomes like pure gold without any dross. In this way one becomes clear of defects and purified for God. And efface the disbelievers in the wadis of dispersion tafriqa. As for the scum it passes away as dross [13:17].