What is the nature of the Qur’an’s authority and its role in Islamic legislation according to Islamic custom and heritage?

The Qur'an was revealed by Allah as a law and a reference for people, so that they may deem permissible what it permits and forbid what it forbids, and obey its commands and avoid its prohibitions. It contains news of what came before us, tidings of what will come after us, and rulings for what is between us. Allah Almighty said: "We have not neglected in the Register a thing," and He said: "This day I have perfected for you your religion." The Sunnah came to clarify and complete the Qur'an. The Prophet, peace and blessings be upon him, said: "Indeed, I have been given the Qur'an and something similar to it along with it." Allah commanded that we refer to both of them in case of dispute: "And if you disagree over anything, refer it to Allah and the Messenger." Referring to Allah means referring to the Qur'an, and referring to the Messenger means referring to the Sunnah. Thus, the Qur'an is the primary source of legislation, followed by the Sunnah.