You are all free to add to THE FOUNDATION and go beyond the doctrine of CHRIST
The doctrine of Christ is found in 66 Books, from Genesis to Revelation and is our foundation is it not?
2 Timothy 3:16-17 NKJV
16 All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, 17 that the man of God may be complete, thoroughly equipped for every good work.
The entirety of scripture is our doctrine and gospel. We shouldn't argue from any point other than scripture
The confusion present before in the thread was not due to a lack of agreeing with your premise... it's that the first few posts were slightly disjointed. I think all has been made clear though so far