مَن كَفَرَ بِٱللَّهِ مِنۢ بَعۡدِ إِيمَٰنِهِۦٓ إِلَّا مَنۡ أُكۡرِهَ وَقَلۡبُهُۥ مُطۡمَئِنُّۢ بِٱلۡإِيمَٰنِ وَلَٰكِن مَّن شَرَحَ بِٱلۡكُفۡرِ صَدۡرٗا فَعَلَيۡهِمۡ غَضَبٞ مِّنَ ٱللَّهِ وَلَهُمۡ عَذَابٌ عَظِيمٞ

man kafara billaahi mim ba'di eemaanihee illaa man ukriha wa qalbuhoo mutmma'innum bil eemaani wa laakim man sharaha bilkufri sadran fa'alaihim ghadabum minal laahi wa lahum 'azaabun 'azeem

Any one who, after accepting faith in Allah, utters Unbelief,- except under compulsion, his heart remaining firm in Faith - but such as open their breast to Unbelief, on them is Wrath from Allah, and theirs will be a dreadful Penalty.

— Al-Nahl (ٱلنَّحْل), 16:106