According to the Father anything added to His Word other than His Will is heresy.
The Jews had Scripture. They added Tradition. Look where that left the Sadduces and Pharasees.
Today we all have an equal opportunity in fellowship with Him through faith in Christ to perform good works through faith in Him. We all are our own priests through faith in the High Priest, our Lord and Savior Christ Jesus.
Protestants added "sola scriptura" to His Word against His will. Therefore, according to your own criterion, 'sola scriptura' is heresy.
-A8