مَنْ كَفَرَ بِاللّٰهِ مِنْۢ بَعْدِ اِيْمَانِهٖٓ اِلَّا مَنْ اُكْرِهَ وَقَلْبُهٗ مُطْمَىِٕنٌّۢ بِالْاِيْمَانِ وَلٰكِنْ مَّنْ شَرَحَ بِالْكُفْرِ صَدْرًا فَعَلَيْهِمْ غَضَبٌ مِّنَ اللّٰهِ ۗوَلَهُمْ عَذَابٌ عَظِيْمٌ ( النحل: ١٠٦ )
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 (an-Naḥl 16:106)
Sahih International:
Whoever disbelieves in [i.e., denies] Allah after his belief... except for one who is forced [to renounce his religion] while his heart is secure in faith. But those who [willingly] open their breasts to disbelief, upon them is wrath from Allah, and for them is a great punishment; (An-Nahl [16] : 106)
1 Mufti Taqi Usmani
Whoever rejects his faith in Allah after having believed in Him - not the one who is compelled (to utter a word of disbelief) under duress while his heart is at peace with Faith, but the one who has laid his breast wide open for disbelief - upon such people is the wrath of Allah, and for them there is a heavy punishment.