وَالَّذِينَ يُتَوَفَّوْنَ مِنْكُمْ وَيَذَرُونَ أَزْوَاجًا يَتَرَبَّصْنَ بِأَنفُسِهِنَّ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا فَإِذَا بَلَغْنَ أَجَلَهُنَّ فَلَا جُنَاحَ عَلَيْكُمْ فِيمَا فَعَلْنَ فِي أَنفُسِهِنَّ بِالْمَعْرُوفِ وَاللَّهُ بِمَا تَعْمَلُونَ خَبِيرٌ  وَلَا جُنَاحَ عَلَيْكُمْ فِيمَا عَرَّضْتُمْ بِهِ مِنْ خِطْبَةِ النِّسَاءِ أَوْ أَكْنَنتُمْ فِي أَنفُسِكُمْ عَلِمَ اللَّهُ أَنَّكُمْ سَتَذْكُرُونَهُنَّ وَلَكِنْ لَا تُوَاعِدُوهُنَّ سِرًّا إِلَّا أَنْ تَقُولُوا قَوْلًا مَعْرُوفًا وَلَا تَعْزِمُوا عُقْدَةَ النِّكَاحِ حَتَّى يَبْلُغَ الْكِتَابُ أَجَلَهُ وَاعْلَمُوا أَنَّ اللَّهَ يَعْلَمُ مَا فِي أَنفُسِكُمْ فَاحْذَرُوهُ وَاعْلَمُوا أَنَّ اللَّهَ غَفُورٌ حَلِيمٌ (2: 234-35)

And those of you who die and leave widows behind, they should keep themselves in waiting for four months and ten days. Then when they have fulfilled their term, there is no blame on you about what they do with themselves in accordance with the norms [of society]. And Allah is well acquainted with what you do. And there is also no blame on you if you tacitly send a marriage proposal to these women or hold it in your hearts. Allah knows that you would definitely talk to them. [Do so] but do not make a secret contract. Of course you can say something in accordance with the norms [of the society]. And do not decide to marry till the law reaches its term. And know that Allah has knowledge of what is in your hearts; so be fearful of Him and know that Allah is Most forgiving and Most Forbearing. (2:234-5)

    The above quoted verses of Surah Baqarah mention the directive of ‘Iddat (waiting period) for widows. 
    The first thing mentioned is that the ‘Iddat of a widow is four months and ten days.¹ In contrast to the ‘Iddat of a divorced lady, the ‘Iddat of a widow has been extended by forty days. The reason is that while a husband has been asked to divorce his wife in the period of purity (in which he has had no sexual intercourse with her), obviously no such requirement can be proposed in the case of a widow. It is to exercise care that forty days have been added by the Qur’an to the waiting period of a woman who loses her husband.
    The second thing stated is that after the waiting period expires, the wife is free to do whatever she deems appropriate for herself.  However, she should follow the norms of the society in this matter. In other words, she should not indulge in any activity which damages the repute, honor and integrity of the family nor the conventions of society. If all this is kept in consideration, then no blame can be caste on her or her guardians. Writes Imam Amin Ahsan Islahi:

What is implied is that one should not blame and censure one another without any reason by equating all un-islamic customs with Islam. On the one hand, a situation should not develop where the guardians of the widow or the heirs of the deceased husband are censured due to the implication that they got tired of the wife (thus letting her leave) much before she could fully mourn the loss of her husband. On the other hand, circumstances should not deteriorate to where the widow herself is censured simply because she became interested in re-marrying soon after her husband’s death. In all cases, only the bounds of the Almighty should be observed and one should remember that the Almighty is aware of all the deeds of His creatures.²

    The third thing stated is that if a person wants to marry a widow, then it is according to the norms that he confirm his desire during her waiting period or inform her of his intentions in a very tacit manner. However, it is not permitted that he, without considering the sentiments of the affected family, send a marriage proposal to the widow or make some hidden agreement with her. On such occasions, whatever is said must never exceed the bounds of sympathy and expression of condolences. Consequently, the verses forewarn a person that since it is definite that he would express his intention in such a situation, it should not be in the form of a marriage proposal or some hidden or open agreement. This intention should be expressed in a manner that is befitting to the situation and in accordance with the norms of the society. Of course, once the waiting period expires, a person can decide to marry such a lady. At that time, he cannot be blamed in any way.  
    It stems from this directive that the behavior of the widow should also be befitting to the situation she finds herself in. On these very grounds, the Prophet (sws) directed such women to spend their ‘Iddat in the house of their deceased husband in a state of mourning and to refrain from embellishing themselves. He is reported to have said:

المتوفى عنها زوجها لا تلبس المعصفر من الثياب ولا الممشقة ولا الحلي ولا تختضب ولا تكتحل )سنن أبي داود ‘ رقم: 1960 (

A widow should not wear colored clothes, neither golden nor red nor ochre. She should not adorn jewelry nor put on henna or stain her eyes with antimony. (Abu Da’ud, No: 1960)

    Should such a wife be provided with residence and maintenance during this period? The Qur’an has answered this question further down in the surah: Husbands should make a will in favor of their wives for the provision of one year’s residence and maintenance, except if the wives themselves leave the house or take any other similar step³:

وَالَّذِينَ يُتَوَفَّوْنَ مِنْكُمْ وَيَذَرُونَ أَزْوَاجًا وَصِيَّةً لِأَزْوَاجِهِمْ مَتَاعًا إِلَى الْحَوْلِ غَيْرَ إِخْرَاجٍ فَإِنْ خَرَجْنَ فَلَا جُنَاحَ عَلَيْكُمْ فِي مَا فَعَلْنَ فِي أَنفُسِهِنَّ مِنْ مَعْرُوفٍ وَاللَّهُ عَزِيزٌ حَكِيمٌ (2: 240)

And those of you who die and leave widows should bequeath for their widows a year’s provision and [bequeath] that [in this period] they shall not be turned out of their residences; but if they themselves leave the residence, there is no blame on you for what they do with themselves according to the norms of society. And Allah is Exalted in Power, Wise. (2:240)