Assalam alaikum,
You are aware that the Sunnah refers to the commands, prohibitions, sayings, actions and tacit approvals of the Messenger of Allah, Prophet Muhammad, Sallallahu alaihi Wasallam. The whole of the Sunnah falls under the Command of Allahu, Subhanahu Wa Ta'ala, in His Book: "Whatsoever the Messenger gives you [then] take it and whatsoever he prohibits you from, [then] refrain from it." [Surat al-Hashar-59:7 ].

We must kick against today's casual attitude with which some Muslims, unfortunately, discard the Sunnah of our Prophet, peace be upon him. Allah Ta'ala repeatedly links obedience of Allah to obedience of His Messenger. Allah says: "And whosoever obeys the Messenger, thereby obeys Allah". [4:80] There are many other verses (Ayats) of the Qur'an condemning having a 'Qur'an only' approach to issues. To divorce the Sunnah from Islam is to render Islam ineffective.... for example, the Qur'an directs us to pray, but without the Sunnah, how would we know how to pray or pay/give the Zakkat?