Sura al-Naḥl 16:106

مَن كَفَرَ بِٱللَّـهِ مِنۢ بَعْدِ إِيمَٰنِهِۦٓ إِلَّا مَنْ أُكْرِهَ وَقَلْبُهُۥ مُطْمَئِنٌّۢ بِٱلْإِيمَٰنِ وَلَٰكِن مَّن شَرَحَ بِٱلْكُفْرِ صَدْرًا فَعَلَيْهِمْ غَضَبٌ مِّنَ ٱللَّـهِ وَلَهُمْ عَذَابٌ عَظِيمٌ

man kafara billāhi min baʿdi īmānihi illā man ukriha wa-qalbuhu muṭmaʾinnun bi-l-īmāni wa-lākin man sharaḥa bil-kufri ṣadran faʿalayhim ghaḍabun mina allāhi wa-lahum ʿadhābun ʿaẓīmun

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.