Sufyaan Ath-Thawree, raHimahullaah, said: "The excellence of knowledge is due only to the fact that it causes a person to fear and obey Allaah, otherwise it is just like anything else."
[Related by ibn Rajab]
Al-Hasan al-Basree, raHimahullaah, said: "Whoever learns something in the name of Allaah, seeking that which is with Him, he will win. And whoever learns something for other than Allaah, he will not reach the goal, nor will his acquired knowledge bring him closer to Allaah."
[Related by Ibn ul Jawzee]
Ibn Mas`ood, raDiallaahu `anhu, said: "True knowledge is not measured in relationship to how much you memorize and then narrate, but rather, true knowledge is an expression of piety [protecting oneself from what Allaah prohibited and acting upon what He mandated]."Also, "Study and act upon what you learn."
[Related by Abu Na`eem]