وَٱلَّذِينَ يُتَوَفَّوۡنَ مِنكُمۡ وَيَذَرُونَ أَزۡوَٰجٗا يَتَرَبَّصۡنَ بِأَنفُسِهِنَّ أَرۡبَعَةَ أَشۡهُرٖ وَعَشۡرٗاۖ فَإِذَا بَلَغۡنَ أَجَلَهُنَّ فَلَا جُنَاحَ عَلَيۡكُمۡ فِيمَا فَعَلۡنَ فِيٓ أَنفُسِهِنَّ بِٱلۡمَعۡرُوفِۗ وَٱللَّهُ بِمَا تَعۡمَلُونَ خَبِيرٞ
And those of you who die and leave wives behind them, they (the wives) shall wait (as regards their marriage) for four months and ten days, then when they have fulfilled their term, there is no sin on you if they (the wives) dispose of themselves in a just and honourable manner (i.e. they can marry). And Allah is Well-Acquainted with what you do.
وَلَا جُنَاحَ عَلَيۡكُمۡ فِيمَا عَرَّضۡتُم بِهِۦ مِنۡ خِطۡبَةِ ٱلنِّسَآءِ أَوۡ أَكۡنَنتُمۡ فِيٓ أَنفُسِكُمۡۚ عَلِمَ ٱللَّهُ أَنَّكُمۡ سَتَذۡكُرُونَهُنَّ وَلَٰكِن لَّا تُوَاعِدُوهُنَّ سِرًّا إِلَّآ أَن تَقُولُواْ قَوۡلٗا مَّعۡرُوفٗاۚ وَلَا تَعۡزِمُواْ عُقۡدَةَ ٱلنِّكَاحِ حَتَّىٰ يَبۡلُغَ ٱلۡكِتَٰبُ أَجَلَهُۥۚ وَٱعۡلَمُوٓاْ أَنَّ ٱللَّهَ يَعۡلَمُ مَا فِيٓ أَنفُسِكُمۡ فَٱحۡذَرُوهُۚ وَٱعۡلَمُوٓاْ أَنَّ ٱللَّهَ غَفُورٌ حَلِيمٞ
And there is no sin on you if you make a hint of betrothal or conceal it in yourself, Allah knows that you will remember them, but do not make a promise of contract with them in secret except that you speak an honourable saying according to the Islamic law (e.g. you can say to her, "If one finds a wife like you, he will be happy"). And do not consummate the marriage until the term prescribed is fulfilled. And know that Allah knows what is in your minds, so fear Him. And know that Allah is Oft-Forgiving, Most Forbearing.