اَفَمَنْ شَرَحَ اللّٰهُ صَدْرَهٗ لِلْاِسْلَامِ فَهُوَ عَلٰى نُوْرٍ مِّنْ رَّبِّهٖ ۗفَوَيْلٌ لِّلْقٰسِيَةِ قُلُوْبُهُمْ مِّنْ ذِكْرِ اللّٰهِ ۗ اُولٰۤىِٕكَ فِيْ ضَلٰلٍ مُّبِيْنٍ ( الزمر: ٢٢ )
Afaman sharahal laahu sadrahoo lil Islaami fahuwa 'alaa noorim mir Rabbih; fa wailul lilqaasiyati quloobuhum min zikril laah; ulaaa'ika fee dalaalim mubeen (az-Zumar 39:22)
Sahih International:
So is one whose breast Allah has expanded to [accept] IsLam and he is upon [i.e., guided by] a light from his Lord [like one whose heart rejects it]? Then woe to those whose hearts are hardened against the remembrance of Allah. Those are in manifest error. (Az-Zumar [39] : 22)
1 Mufti Taqi Usmani
So I ask about a person whose heart Allah has opened up for Islam, and consequently he proceeds in a light from his Lord. (Can he be equal to the one whose heart is hardened?) So, woe to those whose hearts are too hard to remember Allah. Those are wandering in open error.