Sahih al-bukhari:5022 Chapter: How the Divine Revelation used to be revealed and what was the first thing revealed Book 66, Hadith 44

Narrated Talha: I asked `Abdullah bin Abi `Aufa, “Did the Prophet (ﷺ) make a will (to appoint his successor or bequeath
wealth)?” He replied, “No.” I said, “How is it prescribed then for the people to make wills, and they
are ordered to do so while the Prophet (ﷺ) did not make any will?” He said, “He made a will wherein he
recommended Allah’s Book.”