Hakeemul Ummat Hazrat Mawlana Ashraf Ali Thanawi ra said:

“Remember a scholar who after completion of his education does not attend a khanqah (zawiya) for islah (self reformation) is like a person who is satisfied with the wudhu alone and does not proceed to offer the salah (prayers).

Mere learning and teaching is of no use. To be effective they have to be accompanied with the suhba (company) of the ahlul Allah (the pious).”

Ifadhatul yoomiya, volume 5, page 515. Quoted from Albalagh (Urdu) Safar 1427, 50.