عَنْ اِبْنِ عُمَرَ ‏- رَضِيَ اَللَّهُ عَنْهُمَا‏- ; أَنَّ رَسُولَ اَللَّهِ ‏- صلى الله عليه وسلم ‏-قَالَ : { مَا حَقُّ اِمْرِئٍ مُسْلِمٍ لَهُ شَيْءٌ يُرِيدُ أَنْ يُوصِيَ فِيهِ يَبِيتُ لَيْلَتَيْنِ إِلَّا وَوَصِيَّتُهُ مَكْتُوبَةٌ عِنْدَهُ } مُتَّفَقٌ عَلَيْهِ 1‏ .‏‏1 ‏- صحيح .‏ رواه البخاري ( 2738 )‏ ، ومسلم ( 1627 )‏.‏

Allah's Messenger (ﷺ) said: "It is not permissible for a Muslim person, who has something he wants to give as a bequest, to have it for two nights without having his will regarding it written and kept ready with him." .