Musnad Abu Ya'la al-Mawsili 151:62

Narrated to us Muhammad, narrated to us al-Muthanna ibn Bakr, narrated to us ‘Awf, narrated to us Sulayman, from Abu al-Ahwas, from ‘Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Learn the Qur’an, and learn knowledge, and teach it to the people. And learn the laws of inheritance (al-fara’id), and teach them to the people. For I am a man who will be taken [in death], and knowledge will be taken [away] until two men will differ regarding a matter of inheritance and will not find anyone to inform them."