The Messenger of Allah ﷺ said, "It is not right for a Muslim man who has something concerning which he wishes to make a bequest to spend even two nights without having his will written and kept with him."
أن رسول الله ﷺ قال: ما حق امرئ مسلم له شيء يريد أن يوصي فيه يبيت ليلتين إلا ووصيته مكتوبة عنده.
Bukhari related it in the Book of Wills (1) from Nafi, from Abdullah bin Umar, as mentioned. Bukhari also related it in the Book of Wills (2738) through the route of Malik. Muslim related it in the Book of Wills (1627) through other routes from Nafi, with the same wording. This applies to those other than heirs.As for what is reported from Anas bin Malik, who said the Messenger of Allah ﷺ said, "The deprived one is he who is deprived of making his will," this is daif. Ibn Majah related it (2700) from Nasr bin Ali Jahdami, who said, Darust bin Ziyad narrated to us, who said, Yazid Raqashi narrated to us, from Anas bin Malik, as mentioned. Darust bin Ziyad and his teacher Yazid, who is Ibn Aban Raqashi, are both daif.Likewise, what is reported from Abu Hurairah is not sound, who said the Messenger of Allah ﷺ said, "Allah has bestowed upon you, at your death, a third of your wealth as an increase in your good deeds." Ibn Majah related it (2709) from Ali bin Muhammad, who said, Waki narrated to us, from Talha bin Amr, from Ataa, from Abu Hurairah, as mentioned. Its chain is extremely daif, for Talha bin Amr Hadrami Makki is extremely daif. Indeed, Imam Ahmad said, "Worthless, discarded." Bayhaqi also related it through his route (6/269).Likewise, what is reported from Abu Darda, from the Messenger of Allah ﷺ, is not sound, "Allah has bestowed upon you a third of your wealth at your death." Ahmad related it (27482), and Bazzar in Kashf Astar (1382), both from the hadith of Abu Yaman, who said, Abu Bakr bin Abu Maryam narrated to us, from Damra bin Habib, from Abu Darda, as mentioned. Bazzar said, "This has been related through more than one route, and the most prominent one who related it in this matter is Abu Darda, and we know of no other route for it besides this one. Damra and Ibn Abu Maryam are known for transmitting knowledge, and the hadith is acceptable from them." So he said, may Allah have mercy on him.Abu Bakr bin Abu Maryam is Abu Bakr bin Abdullah bin Abu Maryam Ghassani Shami, who is sometimes attributed to his grandfather. He is daif by the agreement of the people of knowledge, and his house had been robbed, after which his mind became confused. As for his teacher Damra bin Habib, who is Zubaydi, he is, as Bazzar said, known for knowledge. Ibn Saad deemed him reliable, Abu Hatim said, "There is no harm in him," and Ajli said, "A trustworthy Shami."On this subject there is also a report from Abu Bakr Siddiq, Muaz bin Jabal, and others, but all of these are daif, even though some may strengthen others.The majority of the people of knowledge held this view, saying that a bequest of a third to those who are not heirs is recommended for one who has the means, provided he does not intend to harm the heirs. Shafii, in his earlier position, and Dawud Zahiri held that a bequest to those who are not heirs is obligatory.