Answered by Sayyidi Habib Umar bin Hafiz (may Allah protect him and benefit us by him)
Do I need permission to read and study religious texts?
There is great benefit in the explanation of the scholars. Furthermore if you have permission (ijazah) from them to read or study a specific text it is more likely to be beneficial and your understanding will be deeper. However, every Muslim who studies these books will benefit, especially if one studies them with love, yearning and desire to travel the path.