Are the Quranic commands and prohibitions more important than the commands and prohibitions of the Prophetic Sunnah, and does violating them incur a greater sin?

The Prophetic Sunnah (definition) is a primary source of Islamic legislation, and its indications concerning rulings are like those of the Quran. Therefore, commands and prohibitions within it, like those in the Quran, entail obligation, prohibition, or other classifications, and determining this depends on the principles of Islamic jurisprudence (Usul al-Fiqh). Prophetic hadiths have been mentioned that affirm the equality of the Sunnah with the Quran in the obligation of acting upon and complying with it, such as the hadiths of Miqdam ibn Ma'dikarib and Al-'Irbad ibn Sariyah, which forbid sufficeing with the Quran alone and indicate that what the Messenger forbade is what Allah forbade. Furthermore, Quranic verses have indicated the obligation to obey the Messenger, peace be upon him, such as His Almighty saying: "He who obeys the Messenger has obeyed Allah."