It is narrated that in his sermon, Imam Ali (AS), the first Shia Imam said:

O’ people, when you become knowledgeable, act upon it (the attained knowledge), maybe you will be guided. The learned one (scholar, knowledgeable person) who acts against his/her knowledge is like a wandering ignorant who does not gain consciousness from (his/her) ignorance; rather the argument against such person (the learned one) is more complete, and the regret to be separated from one’s knowledge is more pronounced in this case than the regret of the ignorant (person) in ignorance. And both are wandering and sleep [1].

[1] Al-Kafi, Vol. 1, Page 44.

Source: en.shafaqna.com