(21) بَابُ قَوْلِ اللَّهِ تَعَالَى: {لِلَّذِينَ يُؤْلُونَ مِنْ نِسَائِهِمْ تَرَبُّصُ أَرْبَعَةِ أَشْهُرٍ} إِلَى قَوْلِهِ: {سَمِيعٌ عَلِيمٌ} {فَإِنْ فَاءُوا} رَجَعُوا
Narrated Anas bin Malik:
Allah's Messenger (ﷺ) took an oath that he would abstain from his wives, and at that time his leg had been sprained (dislocated). So he stayed in the Mashruba (an attic room) of his for 29 days. Then he came down, and they (the people) said, "O Allah's Messenger (ﷺ)! You took an oath to abstain from your wives for one month." He said, "The month is of twenty nine days."
Reference: Sahih al-Bukhari 5289
In-book reference: Book 68, Hadith 38
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 63, Hadith 212