It is reported from Al-Awzâ’î that he said:

Knowledge is what has come from the Companions of Allah’s Messenger – sallallâhu ‘alayhi wa sallam; and what has not come from them is not knowledge.

Al-Dhahabî , Siyar A’lâm Al-Nubalâ` in his biography of Al-Awzâ’î. Ibn ‘Asâkir, Târîkh Dimishq Vol.35 p201.