If our only judge is conscience, how can Jesus claim that it is necessary to know and obey Jesus? A couple of factors here. First, no one will get to heaven by obeying conscience - only because we're already fallen in Adam (can't discuss Original Sin here, and my version isn't the traditional one). Secondly, a person who is obeying ALL of his conscience would not reject Jesus. How so? Imagine a person on a remote island who has never heard the name Jesus - has no idea who He is. Still, everyone has General Revelation (
Romans 1 and 2) which paints a primordial picture of God. This is Yahweh revealing Himself, even if it's not the most crystal-clear portrait conceivable. If he submit to THAT God (who by the way IS Jesus), he will get special revelation, in my view (he'll be born again and will receive the Holy Spirit). Now he has the Inward Witness (Direct Revelation), so if someone comes preaching "Jesus" to him he won't reject it - he will accept it by virtue of the influence of the Inward Witness. In fact he has ALREADY accepted Jesus, not by the five letters J-e-s-u-s, which don't mean much, but because he has now MET Jesus by Direct Revelation. (The Mormons and JW's know the five letters J-e-s-u-s but it does them no good because they've never met HIm).
And this dynamic isn't limited to General Revelation. (In fact it's dubious, given the hardened heart of sinful man, whether General Revelation alone would move a sinner to submit to Yahweh/Jesus). What I'm saying is that most OT saints got saved by the Inward Witness (special revelation) without recourse to General Revelation. In other words, they came to know the Lord - they met the Lord - same way you and I do.
"My sheep listen to my voice. I know them,and they follow me" (Jn 10:27).
Does that answer your question?
Still waiting for one exception to the maxim. (Yawn).