The Old Testament And New Testament

If the Old Testament and New Testament truly were in conflict, the New Testament would be false by default because it already affirms the Old Testament, meaning it would contradict itself and the Old Testament it claims to build off of.  It would still be logically possible even if they did conflict that the Old Testament is true, though.  Its veracity, real or hypothetical, does not philosophically depend on the potential truth of the New Testament, but the opposite is not true: the New Testament cannot be true unless the Old Testament is.  There is no assumption here that either Testament is true, only the fact that the part of the Bible on which the other hangs is not the one most people subjectively like.  It is this dislike that stops so many from realizing this about Christianity.

It is indeed the case that both the Old Testament and New Testament each illuminate certain aspects of Christian theology that the other scarcely touches.  Without the Old Testament, without Mosaic Law more specifically, the Bible would be left with nothing but mostly unhelpful, utterly unclear commands to love, be just, or avoid evil without ever mentioning almost anything specific beyond this.  As any rational person could quickly see here, this would undercut almost everything about the clarity and accessibility of Biblical commands.  No one at all, no matter how thorough a reader or intelligent they are, could possibly realize what the Bible would mean by many of these vague commands of the New Testament with the Old Testament missing.

Likewise, issues like hell and salvation are much more clearly described in the New Testament, to be sure.  The Messianic figure of Christ is only hinted at in mostly vague ways in the Old Testament, though this of course pertains to salvation as well.  The Old Testament clearly describes that the wicked will literally cease to exist (Psalm 73, Ezekiel 18:4), but the New Testament is what actually clarifies the nature of hell as a realm of punishment for unsaved beings.  General soteriology is also given much more detailed attention in the words of Jesus and the apostles than by anything in the Old Testament.  Yes, there are vital things in both Testaments that are given far more precise elaboration in one and not the other!

Even so, it is true that the Old Testament can stand as a set of documents with claims that are philosophically true or at least possible without the New Testament, but the veracity of the New Testament is not even logically possible if it truly contradicted the Old Testament that it so obviously stands on.  In a desperate attempt to protect the popular but glaring misrepresentations of both the Old Testament and New Testament, evangelicals try to pit the latter against the former and side with the latter despite the former being more foundational and thus more theologically important.  They are frightened by the explicit theonomy that the Old Testament plainly teaches and that the new Testament only affirms, but they then embrace heresies with even harsher aspects than legitimately Biblical theonomy, such as eternal conscious torment for all the unsaved.

Shallow Christians and shallow outside analyzers of Christianity merely mistake things for being the other way around.  When most people only assess any worldview, from rationalism to Islam to feminism to Christianity, through the pathetic lens of random person or cultural assumptions, they will always fail to understand an idea and its ramifications except in random bursts and by accident.  Backwards, blatantly false priorities regarding the Old Testament and New Testament have become so normalized in this way that they are mistaken for the true way of understanding the Bible.  Like the fool who thinks they can understand Islam without reading the Quran, making no assumptions, and intentionally reasoning out the claims and ramifications of the actual text, the fool who thinks they can understand the Bible without doing the same perpetuates their own stupidity.