The Ila' and its Rulings
Allah says;
لِّلَّذِينَ يُوْلُونَ مِن نِّسَأيِهِمْ تَرَبُّصُ أَرْبَعَةِ أَشْهُرٍ فَإِنْ فَأوُوا فَإِنَّ اللّهَ غَفُورٌ رَّحِيمٌ
Those who take an oath not to have sexual relation with their wives must wait for four months, then if they return, verily, Allah is Oft-Forgiving, Most Merciful.
Ila' is a type of vow where a man swears not to sleep with his wife for a certain period, whether less or more than four months. If the vow of Ila' was for less than four months, the man has to wait for the vow's period to end and then is allowed to have sexual intercourse with his wife. She has to be patient and she cannot ask her husband, in this case, to end his vow before the end of its term.
It is reported in the Two Sahihs that Aishah said that;
Allah's Messenger swore he would stay away from with his wives for a month. He then came down after twenty-nine days saying;
الشَّهْرُ تِسْعٌ وَعِشْرُون
The (lunar) month is twenty-nine days.
Similar was narrated by Umar bin Al-Khattab and reported in the Two Sahihs.
If the period of Ila' is for more than four months, the wife is allowed in this case to ask her husband, upon the end of the four months, to end the Ila' and have sexual relations with her. Otherwise, he should divorce her, by being forced to do so by the authorities if necessary, so that the wife is not harmed.
Allah said;
لِّلَّذِينَ يُوْلُونَ مِن نِّسَأيِهِمْ
Those who take an oath not to have sexual relations with their wives,
meaning, swear not to have sexual relations with the wife.
This Ayah indicates that the Ila' involves the wife and not a slave-women, as the majority of the scholars have agreed,
تَرَبُّصُ أَرْبَعَةِ أَشْهُرٍ
must wait for four months,
meaning, the husband waits for four months from the time of the vow and then ends the Ila' (if the vow was for four or more months) and is required to either return to his wife or divorce her.
This is why Allah said next;
فَإِنْ فَأوُوا
then if they return,
meaning, to a normal relationship, having sexual intercourse with the wife.
This is the Tafsir of Ibn Abbas, Masruq, Ash-Sha`bi, Sa`id bin Jubayr and Ibn Jarir.
فَإِنَّ اللّهَ غَفُورٌ رَّحِيمٌ
verily, Allah is Oft-Forgiving, Most Merciful.
with any shortcomings that occurred in the rights of the wife because of the vow of Ila'.
Allah said;
وَإِنْ عَزَمُواْ الطَّلَقَ فَإِنَّ اللّهَ سَمِيعٌ عَلِيمٌ