Where does the Bible teach our accountability to each other?
Nowhere, I think.
We will certainly be accountable to God on the final day of judgement, the Bible is very clear on this.
But I can't think of a single verse which teaches that Christians are accountable to each other.
Verses which teach that we should encourage each other, confess our sins to each other (and so on) come close, but they are not the same.
The demanding of accountability to a human judge is more a feature of state rule (in which case it is legitimate) or Roman Catholicism (in which case it is not).