Here's what I tell everyone. Exegesis is difficult (that's why we need Direct Revelation). And due to this complexity, I'll prefer a simple tautology (such as my maxim) over exegesis 10 times out of 10.
You can't refute the maxim because you'd be left with a logical contradiction - the maxim defines justice (as explained recently) and God is not unjust. Therefore it is obvious to me that any exegesis which SEEMS to contradict the maxim must be an error - all we have to do is find another possible interpretation of the passage. Here's the verse.
"He that rejecteth me, and receiveth not my sayings, hath one that judgeth him: the word that I spake, the same shall judge him in the last day."
In my metaphysics, the divine Word exudes from the human body in proper preachinig and evangelism. Example, "Jesus breathed in them and said, Receive ye the Holy [Breath]" (usually mistranslated the 'Holy Spirit').
In several cases, Jesus alluded to the words from His mouth being the actual divine Word, e.g, "You are already clean because of the Word spoken to you" (Jn 15).
Thus going back to your verse, "the [divine] Word that I spake, the same shall judge him in the last day." That takes care of the latter part of the verse. Let's now consider the first part:
"He that rejecteth me, and receiveth not my sayings..."
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 obey 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 ha General Revelation (Romans 1 and 2) which paints a primordial picture of God. If he submit to THAT God, 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, so if somene comes preaching "Jesus" to him he won't reject it - he will accept it by virtue of the influence of the Inward Witness.
John 12:48 is talking about literal words of Jesus that a person will reject and not some inner witness, or some new audible voice, or some new vision, or new dream, etc.
Jesus says to the Father,
"Sanctify them through thy truth: thy word is truth." (John 17:17).
Back in John 12:
"For I have not spoken of myself; but the Father which sent me, he gave me a commandment, what I should say, and what I should speak." (John 12:49).
So Jesus was speaking literal words of what He was to say by the Father. These are the words that Jesus is is referring to in John 12:48.
Back in John 8, Jesus was talking with some Pharisees;
Jesus said to them:
43 "Why do ye not understand my speech?
even because ye cannot hear my word.
44 Ye are of
your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him." (John 8:43-44).
Jesus was not speaking of some divine inner voice that they were not listening to. They were not listening to His actual words and did not understand them because they justified sin or the lusts of their father (the devil). Sin is what prevented them from understanding our Lord's literal and real speech to them.
1 Timothy 6:3-4 says,
3 "If any man teach otherwise, and consent not to wholesome words,
even the words of our Lord Jesus Christ, and to the doctrine which is according to godliness;
4 He is proud, knowing nothing, ..."
So it is because of sin that a person does not know anything (Hence, they are not able to understand Jesus' speech).
Also, here we see in 1 Timothy 6 that there are wholesome words AND words of our Lord Jesus Christ AND the doctrine (teachings) which is according to godliness. I have done a study on the commands in the New Testament, and there are close to 400 or so direct commands in the New Testament for all. This is the doctrine. These are the teachings that is according to godliness. We got plenty of info. in the Bible to guide our lives. There is no need for extra divine knowledge or holy words, etc.; That is how cults are formed.
Jesus talked literally with many and He did not refer to some hidden voice or inner witness. The Spirit convicts the world of sin (John 16:8-9). So while we do have a conscience that can respond to God's Word, our conscience is not the sole guiding factor to give us new information about the faith in the Bible, and be a more accurate guide for our life spiritually. Titus 1:15 says the conscience can be defiled so it is not trustworthy like the Word of God. 1 John 4:1-3 says we are not to believe every spirit but we are to test the spirits to see if they are of God, and it says that any spirit that does not confess that Jesus Christ has come in the flesh is antichrist.
See: I am going back to the Word to prove my case to you.
I am not appealing to some voice.
I am not appealing to some limited conscience.
I am not appealing to some new vision.
I am not appealing to some near death experience.
I am appealing to the Bible.
That is our final word of authority.
The Bible is our ultimate guide.
If you scoff at such a thing, I am afraid for you.
Jesus says that if a person does not receive His words, those words will judge them on the last day (John 12:48). Yet, you think these are not literal words that He once spoke and are recorded in Scripture? If that is so, then I hope that works out for you, but I know it will not. For Jesus was referring to His literal actual words that we can read in Scripture. For Jesus was commanded to speak only what His Father told Him to say. These are the words He was referring to.