Surah Al-Baqarah · Ayah 234

وَٱلَّذِينَ يُتَوَفَّوْنَ مِنكُمْ وَيَذَرُونَ أَزْوَٰجًۭا يَتَرَبَّصْنَ بِأَنفُسِهِنَّ أَرْبَعَةَ أَشْهُرٍۢ وَعَشْرًۭا ۖ فَإِذَا بَلَغْنَ أَجَلَهُنَّ فَلَا جُنَاحَ عَلَيْكُمْ فِيمَا فَعَلْنَ فِىٓ أَنفُسِهِنَّ بِٱلْمَعْرُوفِ ۗ وَٱللَّهُ بِمَا تَعْمَلُونَ خَبِيرٌۭ

Wallazeena yutawaffawna minkum wa yazaroona azwaajai yatarabbasna bi anfusihinna arba'ata ashhurinw wa 'ashran fa izaa balaghna ajalahunna falaa junaaha 'alaikum feemaa fa'alna feee anfusihinna bilma'roof; wallaahu bimaa ta'maloona Khabeer

And those who are taken in death among you and leave wives behind - they, [the wives, shall] wait four months and ten [days]. And when they have fulfilled their term, then there is no blame upon you for what they do with themselves in an acceptable manner. And Allah is [fully] Acquainted with what you do.