soundness of intellect ('aql)

قُل لَّا يَسْتَوِى ٱلْخَبِيثُ وَٱلطَّيِّبُ وَلَوْ أَعْجَبَكَ كَثْرَةُ ٱلْخَبِيثِ ۚ فَٱتَّقُوا۟ ٱللَّهَ يَـٰٓأُو۟لِى ٱلْأَلْبَـٰبِ لَعَلَّكُمْ تُفْلِحُونَ

Say, "Not equal are the evil and the good, although the abundance of evil might impress you." So fear Allāh, O you of understanding, that you may be successful.