The Messenger of Allah ﷺ said, "Abu Hurayrah, learn the laws of inheritance and teach them, for they are half of knowledge. They are forgotten, and they will be the first thing taken away from my ummah."
حدثنا إبراهيم بن المنذر الحزامي حدثنا حفص بن عمر بن أبي العطاف حدثنا أبو الزناد عن الأعرج
قال رسول الله ﷺ يا أبا هريرة تعلموا الفرائض وعلموها فإنه نصف العلم وهو ينسى وهو أول شيء ينزع من أمتي
No references are available.
[Its isnad is daif] Bayhaqi narrated it, 6/209, from the hadith of Hafs bin Umar through this route, and he said, "Hafs bin Umar narrated it alone, and he is not strong." Dhahabi and Busiri both graded the hadith daif because of the aforementioned Hafs.