Is it obligatory for teachers of Islamic studies and religious scholars to teach acting upon the Quran, and what is the legal evidence for that from books of Fiqh, especially the Shafi'i school?

Scholars and students of knowledge are obliged to guide people to act upon the duties and prohibitions mentioned in the Quran, because Allah took a covenant from them to clarify what is in the Book and not conceal it. This becomes even more emphasized if there is no one else to take their place, or if people turn to them seeking clarification of the truth. As for anything other than that, it is recommended, not obligatory.