Musannaf Ibn Abi Shayba 33:1135

Abu Usama narrated to us, from Mis'ar, who said: I heard 'Abd al-A'la al-Taymi saying: Whoever is given knowledge that does not make him weep, it is fitting that he has not been given knowledge that benefits him, because Allah described the scholars, then he recited until His saying: "They fall upon their faces weeping."