Historical analysis is not a judgement of truth. It is a judgement of fact, which is expressly different from the concept of truth. Simply because I am interested in exploring the larger historical context of the Bible in order to better understand Jesus, his followers, the community of believers, what they believed, the texts, the authors, etc., is explicitly not the same thing as avoiding its core message. I must reiterate that what you interpret as the core message in scripture is not necessarily the same core message that all other Christians interpret. This is even true today, with each “non-denomination” and denomination having its own emphasis of faith, taking conflicting stances among themselves on matters some find central to their beliefs. For example, how do you feel about the Presbyterian Church (USA)’s stance permitting same-sex marriage and the ordination of members of the LGBTQ community? There is clearly a question here about defiance of Law, as is often cited from the Old Testament. Do you think this means that PC(USA) is an illegitimate form of Christianity?
Taken out of context, Isaiah 9.6 (9.5 in the Hebrew) can certainly be made to read as though it refers to the messiah as God. For a moment, let us first examine the context. Taken with the rest of the text, it is clear that Isaiah is talking about a sort of god-king who would be capable of rivaling other god-king rulers, namely the Pharaoh of Egypt and the King of Babylon. It is, in fact, from the Babylonian throne that the titles “King of Kings” (Shahanshah) and “Prince of Peace” are derived, long before its formulaic language was adopted by Isaiah. It is also necessary to point out that in the very next verse, Isaiah makes it clear that he is talking about a worldly kingdom to be ruled over by the House of David, and in no place is this kingdom explained to be a heavenly, afterlife kingdom – which would have been a particularly unusual interpretation in a Jewish context. Hellenistic Jews did not believe in an afterlife in the way Christians do, besides the vague, gloomy “gray space” of shadows which most ancients believed in.
Isaiah’s contemporaries the Pharaoh of Egypt and the King of Babylon were each considered divine to some extent, as in fact most kings were some 2,400 years ago. Even today, the monarch is seen as the divine representative on earth. For a group of people spread across a number of small, fragmented states, whose existence seemed on the verge of destruction, it is not only important but imperative that their king be greater or at least on par with the invasive neighbors’. Isaiah’s expected messiah falls directly into this narrative and this context. We should also note that Isaiah’s prophecies were made prior to the Babylonian invasions of the kingdoms of Judah and Israel, and so it was expected that a king would arise shortly to unite the kingdom of David once more against this external threat – and yet this never happened since the expected successor, Hezekiah, died and the Jews were taken into captivity.
Finally, your translation of Isaiah 9.6 is a widespread mistranslation of the Hebrew. It is first worth noting that Isaiah throughout uses the past tense, in particular when speaking about the birth of the coming messiah. If the expected messiah would be the successor to the contemporary worldly kings of Israel and Judah, use of the past tense implies that the messiah had already been born, in which case it is most likely an allusion to Hezekiah; otherwise why use the past tense? The idea that there exists a “prophetic perfect past tense” is not clearly demonstrated in Hebrew, as some on the internet seem to think.
In Hebrew, Isaiah 9.5:
ה כִּי-יֶלֶד יֻלַּד-לָנוּ, בֵּן נִתַּן-לָנוּ, וַתְּהִי הַמִּשְׂרָה,
עַל-שִׁכְמוֹ; וַיִּקְרָא שְׁמוֹ פֶּלֶא יוֹעֵץ, אֵל גִּבּוֹר, אֲבִי-עַד,
Translated, the text reads:
For to us a child is born, to us a son is given; and the government shall be upon his shoulder, and his name shall be called Wonderful One, Counselor of Mighty God, the Father of Eternity, prince of peace.
For a son has been born to us, a son given to us, and the authority is upon his shoulders, and of the wondrous advisor, the mighty God, the everlasting Father, called his name, ‘the prince of peace’.
…and his name will be called, “A wonderful counselor is the mighty God, an everlasting father is the ruler of peace.“
The titles/names are transliterated: Pele-joez-el-gibbor-Abi-ad-sar-shalom
Notice the differences here – that is because in the traditional Christian translation (which dates to the time of Martin Luther), the Hebrew is translated verb, object, subject, when in fact Hebrew must be read verb, subject, object in order to render an accurate translation. This is, incidentally, a great example of how “received doctrine” (tradition, dogma) can adversely affect the true understanding of scripture. Errors like these then become compounded through further translation and transmission. The King James Bible is especially resplendent with these sorts of compounded errors, particularly in the present, and in some instances the problems are so immense that the KJV text does not actually match what any New Testament manuscripts say.
Regarding Isaiah 9.5’s translation: https://i.stack.imgur.com/KaF2N.png
You may also find this link helpful: https://judaism.stackexchange.com/questions/34228/what-does-isaiah-96-mean
Let me ask you, how do you suppose any Jew could square the idea of calling the messiah divine with the notion that there are no other gods besides the one in the Law of Moses? They certainly did not have the ex post facto doctrine of the Trinity to fall back on. Isaiah would never have blasphemed and called the messiah God, but let us suppose for a moment that this translation does indeed refer to the messiah as God. Note the wording for this particular use of God: אֵ֣ל גִּבּ֔וֹר (el-gibbor). This title is often translated as “mighty God,” but it may as easily be “hero-god” – a demigod of sorts, perhaps in the same way as Moses. Moses was not divine, but he was blessed with the divine powers of God, perhaps in the same way David was inspired by the divine powers of God. Perhaps then this refers to a different sort of individual, more in line with Jewish supernatural traditions, but it nevertheless does not necessitate that, in defiance of Law, the messiah be God. Isaiah is talking about a very particular event, in a very particular place, in a very particular moment, under particular stresses, within a particular culture. We cannot simply impose our own translations on the text because we simply believe it justifies the claim that Jesus was divine. To be sure, I am not saying that Jesus was not divine; what I am saying is that a devout Jewish prophet like Isaiah would never go so far as to commit blasphemy by attributing to the mortal messiah the status of the divine. I do very much believe that he would have assigned divine abilities to this individual, abilities which would have very specifically enhanced his skills as a warrior, general, and ruler. It would be through the messiah that God would make clear his intentions precisely because they would not be, in Isaiah’s view, one and the same entities.