In this book, the definition of the Sunnah, the virtue of the Sunnah, the obligation to follow the Sunnah, the status of opinion in the presence of the Sunnah, the necessity of the Sunnah for the understanding of the Holy Quran, the definition of innovation in the eyes of the Imams, and the correct hadiths. The condemnation of heresy has been made clear in the light.