Importance of adab

Adab (arab. أدب) – behaviors prescribed by Sharia norms, including good manners, decency, decency, humanity.
Imam Malik (رحمه الله), said : “My mother, dressing me, told me: “Go to Sheikh Rabi’i and learn adab from him before you start learning knowledge.”
“Tartib al-Madarik” 1/130

Abdullah Ibn al-Mubarak (رحمه الله), referring to the adherents of the hadith, said : “You are more in need of a large number of adab” than a large amount of knowledge.
 “Tarih ad-Dimashq” 32918.

Abdullah Ibn al-Mubarak (رحمه الله), said: “I have been in search of learning adab for thirty years, and in search of knowledge for twenty years. They ( the righteous predecessors ), before demanding knowledge, studied adab.”
“Ghayat al-Nihayya” 1/446

Imam al-Zuhri (رحمه الله), said : “We used to come to a scholar, and what we learned from his adab was more beloved to us than his knowledge.”
Hilyat al-Auliya 4575.