Originally posted by a brother from a different forum.
In al-Khatib al-Baghdadi's 'Mukhtasar Nasihah ila Ahl al-Hadith' (which can be found in the collection 'Majmu'at Rasa'il fi 'Ulum al-Hadith'; p. 109-126), two good pieces of advice stick out:
First, he speaks about the importance of studying Islam from an early age:
"I wrote this book specifically for the student of Hadith, and for everyone in general. What I am about say is an advice from me to him, out of jealousy for him: he should distinguish himself from the one who is pleased with ignorance for himself, and has nobody to assist him in finding the people of virtue. Likewise, he should look to what he spends most of his time in, and what most of his life has been dedicated towards - of the books of the ahadith of the Messenger of Allah, collecting them, researching knowledge of what he has been commanded with, of what is halal, haram, specific, general, obligatory, preferred, permissible, warned against, abrogating, abrogated, etc. from the various types of knowledge, before the time passes in which he has the ability to do this.
It has been narrated from ash-Shafi'i that he said:
"Obtain knowledge before you are tasked with high positions in life, because when you are tasked with positions, there is no way to obtaining knowledge."
It is narrated that Abu Muhammad al-Maruzi said: "It was said that the mud will swallow up the ring so long as it is still soft. In other words, knowledge should be sought after when one is still young, fresh age."
And it has been reported that Amir al-Mu'minin 'Umar bin al-Khattab said: "Gain knowledge before you are given positions of leadership."
Regarding this statement of 'Umar, Abu 'Ubayd (al-Qasim bin Sallam) said: "Learn the knowledge while you are young, before you become leaders to whom others look up. If you do not learn at this age, you will become ashamed to learn when you are older, and you will remain ignorant, and will be forced to take your knowledge from those who are younger than you, and you will be belittled for this."
Second, he mentioned the danger of abandoning taking knowledge from elder scholars, and instead taking it from the youth:
"...and it was narrated that 'Abdullah bin Mas'ud said: "The people will remain upon good so long as they take their knowledge from those who are older then them, those they trust, and their scholars. If they take their knowledge from those who are younger and evil, they are destroyed."
'Abdullah bin Muslim bin Qutaybah asked about this statement of Ibn Mas'ud's, to which he was told: "It means that the people will remain upon good so long as their scholars are older, and not newcomers, as the older one has passed by the enjoyment, hastiness, and foolishness of his youth, and has been granted experience and insight. So, no doubts enter upon his knowledge, and he is not overtaken by his desires, and he is not swayed by greed, and Satan will not cause him to slip as he does with the newcomer."
ِAnd Ibn Hajar said that it is authentically narrated that 'Umar said: "The people will be corrupted as soon as knowledge comes from the young, and the elder one is rebelled against."