بُلُوغُ الْمَرَامِ
Bulugh al-Maram 958
Business Transactions
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] .
Narrated Ibn 'Umar (RA): 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." [Agreed upon].
Sunnah.com reference: Book 7, Hadith 222