Whom is the Earthly authority for determining what Religious groups are acceptable Christian organizations?
According to the “new Apostles” of the NAR, THEY are on par with the 12 Apostles in authority, so if you ask them, it’s them.
If you are asking me about earthly authority, I’d stick with the writings of the original 12 Apostles,
adding those of the Old Testament Prophets, with Christ as chief cornerstone of how the church should be built on earth.
The Word is alive, the Word is God made Flesh, so it is our earthly authority...
There is no earthly authority that is infallible (yes, Roman Catholics will take issue with this statement). Read a good translation of the Bible (the ESV, for example).
Church history and tradition are helpful, but not infallible. (Roman Catholics would disagree again.)