It is not proper for a Muslim who has something to bequeath to stay for three nights without having his will written with him

The legitimacy of making a will and hastening to do so as a means of clarifying it, adhering to the command of the Lawgiver, preparing for death, and contemplating its details and beneficiaries before being distracted by any obstacle.
Wasiyyah (a will): It means a covenant whereby a person entrusts someone to handle something from his wealth after his death, assigns someone to care for his young children, or entrusts someone with any task or matter he owns after his death.
The will is classified into three categories: 1. Recommended: A will that allocates part of one's wealth to be spent in charitable causes or acts of kindness, so the reward continues to reach him after his death. 2. Obligatory: A will that includes any owed rights, whether these are the rights due to Allah Almighty, such as unpaid Zakah, expiation, or similar obligations by Islamic law, or rights due to others, such as debts or entrusted items. 3. Prohibited: A will that exceeds one-third of one's wealth or includes a bequest to an heir.
The merit of Ibn ‘Umar (may Allah be pleased with him and his father) and his hastening to do good deeds and adherence to the commands of the wise Lawgiver.
Ibn Daqīq al-‘Eid said: Allowing two or three nights is to alleviate hardship and difficulty.
Important matters should be documented in writing because it ensures greater accuracy and preserves rights more effectively.