Sahih al-Bukhari 5290
Sahih al-Bukhari · Book 68: Divorce · "Those who take an oath, not to have sexual relations with their wives, must wait four months."
Narrated Nafi`:
حَدَّثَنَا قُتَيْبَةُ ، حَدَّثَنَا اللَّيْثُ ، عَنْ نَافِعٍ ، أَنَّ ابْنَ عُمَرَ ، رضى الله عنهما كَانَ يَقُولُ فِي الإِيلاَءِ الَّذِي سَمَّى اللَّهُ لاَ يَحِلُّ لأَحَدٍ بَعْدَ الأَجَلِ إِلاَّ أَنْ يُمْسِكَ بِالْمَعْرُوفِ، أَوْ يَعْزِمَ بِالطَّلاَقِ، كَمَا أَمَرَ اللَّهُ عَزَّ وَجَلَّ .
Ibn `Umar used to say about the Ila (which Allah defined (in the Holy Book), "If the period of Ila expires, then the husband has either to retain his wife in a handsome manner or to divorce her as Allah has ordered."