The Sunnah is Islaam and Islaam is the Sunnah
Imaam al-Barbahaari (rahimahullaah) said:
All praise is for Allaah who guided us to Islaam and blessed us with it and placed us in the best nation, so we ask Him to grant us that we keep to that which He loves and is pleased with and avoid that which He hates and which angers Him.
Know that Islam is the Sunnah, and the Sunnah is Islaam and one of them cannot be established without the other.
Taken from Kitaab Sharh us-Sunnah of Imaam al-Barbahaari