"It is not right for a Muslim that two nights, and in one narration, three nights pass on him, but that his will be written, if he has something to make a will for."

His rightful heirs and their proportions have been fixed already by Allah. The financial rights of others which he is holding or his financial rights which others are holding must be recorded. His debtors and creditors must be listed clearly and even what he owes to Allah. This hadith also teaches us that we must make our will and update it regularly. Whenever any changes come about in our matters, we must note it.

The Virtues of Making a Will
"He who dies on his wasiyat (having made a will) dies on a (clear) path (i.e a clear path, leaving no disputes or unresolved issues for his family and making the distribution of the estate easy), he dies on sunnat, on the fear of Allah, martyrdom and he dies forgiven.

Subhanallah! What great virtues for making and keeping one's will ready. Five great boons are promised:

1. He dies on a clear path, how nice to depart, leaving no disputes behind.
2. On sunnah – could there be something greater to ask for.
3. He dies on taqwa – On taqwa Allah promises a way out from every difficulty. What greater difficulty can there be than death. By having one's will ready, one is promised freedom from this difficulty.4. And on Shahaadat – Rasulullah (Salllahu alaihi Wasallam) constantly desired to return to the dunia to become a shaheed (martyr) again and again. Sayyedina Umar (RA) made dua for shahaadat. By having made a will, a person acquires this great stage. Or "on shahaadat" means dying having given evidence of all his financial matters.
5. And he dies forgiven – To die free of sin ensures direct entry into jannat.