Islaam is the Sunnah, and the Sunnah is Islaam
The author (Imaam al-Barabahaaree) may Allah have Mercy on him stated:
"Know that Islaam is the Sunnah and the Sunnah is Islaam and neither of them can be established without the other."
Explanation (Shaykh Rabee' bin Hadee al-Madkhalee, may Allah preserve
بسم الله الرحمن الرحيم
A questioner asks: 'What is the ruling on joining Islaamic groups and parties?'
Answer: "As for the one who joins the way of the salaf, then this is that which is upon the truth. And whatever differs from that, then it is separation. It is mentioned in the hadeeth