The best person of this Din are going to come.
Allahu Ra'ufur Rahiim.
Qur'an Kalamullaah,
Sunnah is from Rasulullah and Jibril 'Alaihi Salaam bi idznillah.
There are things which aren't explicitly mentioned in Al Qur'an, but implied in
QS.2:129. Our Lord! And raise up in their midst a messenger from among them who shall recite unto them Thy revelations, and shall instruct them in the Scripture and in wisdom (HIKMAH) and shall make them grow. Lo! Thou, only Thou, art the Mighty, Wise.
An Nisaa(4):065. But nay, by thy Lord, they will not believe (in truth) until they make thee JUDGE of what is in dispute between them and find within themselves no dislike of that which thou decidest, and submit with full submission.
So I mean Hikmah and JUDGE here is the Sunnah of Rasulullah, and in Al Hadits we're learning what JIBRIL 'ALAIHI WA SALAAM said to Rasulullah which weren't put in Al Qur'an, and As Sunnah was the result of the knowledge of Rasulullah as well as his sight to Ghaib (unseen things) which was his ability in his life given by Allah.
There are many example where things that aren't mention in Al Qur'an but could determine whether our IBADAH (worship) being accept or not.
For example: Thou (Malickabrother) won't find about the prohibition of doing Shalat in menses, only the prohibition of having intercourse while in menses (for wife).
Assalamu'alaikum wa rahmatullaahi wa barakaatuh.