Mishkat al-Masabih 7 Fasting كتاب الصوم 138

وَعَنْ عَائِشَةَ: أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يَعْتَكِفُ الْعَشْرَ الْأَوَاخِرَ مِنْ رَمَضَانَ حَتَّى تَوَفَّاهُ اللَّهُ ثُمَّ اعْتَكَفَ أَزْوَاجُهُ مِنْ بعده

‘A’isha said that the Prophet used to engage in private devotions in the mosque during the last ten nights of Ramadan till God took him, and then his wives followed this practice after his death.* * Mirqat says that the Prophet’s wives observed periods of seclusion for devotion, not in the mosque but in their houses. (Bukhari and Muslim.)