عَنِ ابْنِ عُمَرَ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ كَانَ إِذَا اعْتَكَفَ طُرِحَ لَهُ فِرَاشُهُ أَوْ يُوضَعُ لَهُ سَرِيرُهُ وَرَاءَ أسطوانه التَّوْبَة. رَوَاهُ ابْن مَاجَه

Ibn ‘Abbas reported God’s messenger as saying about one who observes a period of private devotion in a mosque, “He turns away from sins and he is rewarded for good deeds like one who does all good deeds.” Ibn Majah transmitted it.