Abu Umaiuah رضي الله عنه narrates that the Messenger of Allah صلى الله عليه وسلم  said:

“One of the signs of the Hour is that knowledge will be sought from the Asaaghir (small ones in age or status).”

(Narrated by Ibnul Mubarak in Zuhd # 61, Tabrani in Kabir # 908, Awsat # 8140, Khatib in Jame’ Li Akhlaq # 158) Its sanad is hasan. Ibn Lahee’ah’s student is Abdullah ibnul Mubarak.

Umar رضي الله عنه  said: “The people’s doom is when ilm comes from the young ones in defiance of the elders; and the people’s safety is when ilm comes from the elders and the young ones follow.” Ibn Hajr said its sanad is saheeh.

(See Faidhul Qadeer 2/533 & Tanweer Sharh Jame Sagheer 4/123) 

Ibnul Mubarak was asked who are the asaaghir? He replied: “Those who speak out of whim. As for the young one who narrates from an elder then he is not small.”

(Ta’leeq of Muhaddith Habeebur Rahman A’zmi on Zuhd of Ibnul Mubarak pg. 64)