The Ruling of Studying the Arab Literature under the People of Innovations‏

Ash-Shaykh al-Uthaymeen, may Allah have mercy upon him, said when explaining the statement of Shaykh Bakr bin Zayd regarding study under an innovator: 
What is evident from the speech of the Shaykh (Bakr bin Zayd) is that we should not sit under him (the innovator) due to it necessitating two defects; the first defect is him (the innovator) becoming deceived of himself whereas he assumes he is upon uprightness; the second defect is the people become deceived of him, whereas the people and the students will regularly go to him. Add to that is the layman does not make a distinction between the science of grammar from the science of A'qeedah, so due to this we absolutely do not see for any individual to sit under the people of innovations and desires even if he may only find the knowledge of the Arab literature with them."

Reference: Sharhu Hilyati Taalibil 'ilm, page 111

Also the Shaykh, may Allah have mercy upon him, was asked: 
What is the ruling of studying under Ahlul Bid'ah, the likes of al-Ash'arees and others in other than (the field 
of) their innovation?

A: « Generally it is not appropriate to study under
Ahlul bid'ah. 

Reference: Sharhu Saheeh Muslim (38/1) print: al-
Islaamiyyah.

Translated by: Abu Fajr Abdul Fataah al-Kanadi as-Somaalee.