Shaykh Abdullah Bukhari (hafidahullah),

“Many people are deprived of knowledge due to deficiency in good manners, Imam ibn Sireen said,
كانوا يتعلمون الهدي و الصمت كما يتعلمون العلم

(Shaykh Abdullah explains)
They (the salaf) used to learn manners just as they used to learn knowledge. It’s hoped you have read in some of the biographies of the scholars and rulers, that they would bring teachers of good manners and etiquettes to their children.

So, (in conclusion) a student of knowledge without manners is deficient and his lack of, or deficiency in manners is a cause for his being deprived (of good).”

Exp Three Fundamental Principles Lesson 1