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
Q: "What is the degree of authenticity of the hadeeth "Differing of my Ummah is a Mercy (Rahmah)"' ?
A: "It is not authentic. This is from the speech of some of the salaf, from the speech of Qaasim ibn Muhammad regarding differing of the Companions of the Prophet (ﺻﻠﻰ الله عليه و سلام),