Jehovah’s Witnesses, who claim to “reason from scripture”, using it as their sole authority. And they, in fact, ‘even deny the Master who bought them’ by denying His divinity, which they argue against via scripture, as Arian did in similar manner centuries before.
Yes, we can hear and recognize the voice of God, we can glean many truths and gems of wisdom, but we can easily be misled regarding the teachings of Christ and the true nature of the gospel.
Most heresies are born from misunderstandings of scripture.
We’re not speaking of individuals, who, of course, can be false teachers, but rather about the Church, the pillar and foundation of truth, as 1 Tim 3:15 puts it, the Church as the authoritative interpreter of scripture, along with her own, lived tradition since the beginnings of Christianity, since a time before one word of the New Testament was written. The Church is precluded from error in matters of faith and morals; somebody has to be or else we can’t be assured of knowing the gospel with accuracy, in the fullness of truth as its been put. The bible was simply never meant to be a catechism-it is both the work of the Church with God Who inspired her people to write it and her continued resource to His Word. In any case, the bible cannot interpret itself; that requires a living, chosen, authority, otherwise disagreement often occurs.