[UnbelievingScumOnTheOtherSide]

There is no authority from the New Testament claiming that the New Testament, or the Bible, is the sole authority.

There is no authority for anything else's claim to authority in Christianity, and certainly none in contradiction to it. So there you have it, it is redundant or in contradiction. There are no other possibilities.

[mike182d]

There is no authority for anything else's claim to authority in Christianity,

How about the institution that deemed the current collection of writings in the NT as authoritative? Or did they not have the authority to deem it as such in the 4th Century?