Hadith
حَدَّثَنَا مُحَمَّدُ بْنُ مَعْمَرٍ، حَدَّثَنَا رَوْحُ بْنُ عَوْفٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَا حَقُّ امْرِئٍ مُسْلِمٍ يَبِيتُ لَيْلَتَيْنِ وَلَهُ شَىْءٌ يُوصِي بِهِ إِلاَّ وَوَصِيَّتُهُ مَكْتُوبَةٌ عِنْدَهُ " .
It was narrated from Ibn 'Umar that the Prophet (ﷺ) said:“The Muslim man has no right to spend two nights, if he has something for which will should be made, without having a written will with him.”
Sahih · Al-Albani
Sunan Ibn Majah 2702 ·Book 22, Hadith 8·Also available on sunnah.com·