Divine testing and purification

مَّا كَانَ ٱللَّهُ لِيَذَرَ ٱلْمُؤْمِنِينَ عَلَىٰ مَآ أَنتُمْ عَلَيْهِ حَتَّىٰ يَمِيزَ ٱلْخَبِيثَ مِنَ ٱلطَّيِّبِ ۗ وَمَا كَانَ ٱللَّهُ لِيُطْلِعَكُمْ عَلَى ٱلْغَيْبِ وَلَـٰكِنَّ ٱللَّهَ يَجْتَبِى مِن رُّسُلِهِۦ مَن يَشَآءُ ۖ فَـَٔامِنُوا۟ بِٱللَّهِ وَرُسُلِهِۦ ۚ وَإِن تُؤْمِنُوا۟ وَتَتَّقُوا۟ فَلَكُمْ أَجْرٌ عَظِيمٌ

Allāh would not leave the believers in that [state] you are in [presently] until He separates the evil from the good. Nor would Allāh reveal to you the unseen. But [instead], Allāh chooses of His messengers whom He wills, so believe in Allāh and His messengers. And if you believe and fear Him, then for you is a great reward.