To recommend the Book of Allah عز وجل
حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ، حَدَّثَنَا مَالِكُ بْنُ مِغْوَلٍ، حَدَّثَنَا طَلْحَةُ، قَالَ سَأَلْتُ عَبْدَ اللَّهِ بْنَ أَبِي أَوْفَى أَوْصَى النَّبِيُّ صلى الله عليه وسلم فَقَالَ لاَ. فَقُلْتُ كَيْفَ كُتِبَ عَلَى النَّاسِ الْوَصِيَّةُ، أُمِرُوا بِهَا وَلَمْ يُوصِ قَالَ أَوْصَى بِكِتَابِ اللَّهِ.
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."