"It is not befitting for a Muslim who has anything concerning which a will should be made, to abide for two nights without having a written will with him." (Using translation from Nasāʾī 3616)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ مَا حَقُّ امْرِئٍ لَهُشَيْءٌ يُوصِي فِيهِ يَبِيتُ لَيْلَتَيْنِ إِلَّا وَوَصِيَّتُهُ عِنْدَهُ مَكْتُوبَةٌ