In the name of Allah, the Gracious, the Merciful
Al-Nawawi records in his book Riyad al-Salihin:
Abdullah ibn Umar, may Allah be pleased with him, reported:
كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَعْتَكِفُ الْعَشْرَ الْأَوَاخِرَ مِنْ رَمَضَانَ
The Messenger of Allah, peace and blessings be upon him, would seek spiritual retreat in the mosque in the last ten nights of Ramadan.
Source: Ṣaḥīḥ al-Bukhārī 2025, Grade: Muttafaqun Alayhi
Aisha, may Allah be pleased with her, reported:
أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ كَانَ يَعْتَكِفُ الْعَشْرَ الْأَوَاخِرَ مِنْ رَمَضَانَ حَتَّى تَوَفَّاهُ اللَّهُ عَزَّ وَجَلَّ ثُمَّ اعْتَكَفَ أَزْوَاجُهُ مِنْ بَعْدِهِ
The Prophet, peace and blessings be upon him, would seek spiritual retreat in the mosque during the last ten nights of Ramadan, until Allah Almighty caused him to pass away. His wives continued to perform the retreat after him.
Source: Ṣaḥīḥ al-Bukhārī 2026, Grade: Muttafaqun Alayhi
Abu Huraira, may Allah be pleased with him, reported:
كَانَ يَعْرِضُ عَلَى النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الْقُرْآنَ كُلَّ عَامٍ مَرَّةً فَعَرَضَ عَلَيْهِ مَرَّتَيْنِ فِي الْعَامِ الَّذِي قُبِضَ فِيهِ وَكَانَ يَعْتَكِفُ كُلَّ عَامٍ عَشْرًا فَاعْتَكَفَ عِشْرِينَ فِي الْعَام الَّذِي قُبِضَ فِيهِ
The Prophet, peace and blessings be upon him, would review the Quran once every year in Ramadan and he reviewed it twice in the year he passed away. The Prophet would seek spiritual retreat in the mosque for ten days every year and he secluded himself for twenty days in the year he passed away.
Source: Ṣaḥīḥ al-Bukhārī 4998, Grade: Sahih
Imam al-Shafi’i, may Allah have mercy on him, said:
وَمَنْ أَرَادَ الِاقْتِدَاءَ بِالنَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي الِاعْتِكَافِ فِي الْعَشْرِ الْأَوَاخِرِ مِنْ رَمَضَانَ فَيَنْبَغِي أَنْ يَدْخُلَ الْمَسْجِدَ قَبْلَ غُرُوبِ الشَّمْسِ لَيْلَةَ الْحَادِي وَالْعِشْرِينَ مِنْهُ
Whoever desires to follow the example of the Prophet, peace and blessings be upon him, in practicing spiritual retreat in the mosque during the last ten nights of Ramadan, he should enter the mosque before the setting of the sun on the twenty-first night.
Source: al-Majmū’ Sharḥ al-Muhadhdhab 6/475
Success comes from Allah, and Allah knows best.