Imaam Ahmad (rahimahullaah) stated:
(There) is nothing equal to knowledge, for the one who makes his intention correct (i.e. sincere). So they (i.e. the people) said: And how do (we) make the intention correct (i.e. sincere) O father of Abdullaah?! He said: You make an intention to remove ignorance from yourself and others.
[Aadaab Ash-Sharee’ah’ 2/45, by Ibn Muflih (rahimahullaah)]