As a follow up to my comments to this intriguing question, I want to highlight the critical issue regarding one of these divisions. As mentioned by the OP, the divisions of chapters is NOT a Jewish invention, however has been considered mainstream and for the most part accepted.
Although this is the case today, there DOES EXIST some differences in chapter divisions in Tanach versus a christian translation.
This is for 3 reasons:
- Some for the sake of readability for Non-Jews
- Some beginning verses, for example in Psalms, are counted as “titles” and verse 1 in the christian translation would actually be verse 2 in the Tanach
- And others were purposeful distortions for the sake of deception, as I will attempt to elucidate below.
In Tanach, Isaiah chapter 8 ends with verse 23.
(22) And he shall look to the land, and behold, distress and darkness, weariness of oppression, and to the darkness he is lost. (23) For there is no weariness to the one who oppresses her; like the first time, he dealt mildly, [exiling only] the land of Zebulun and the land of Naftali, and the last one he dealt harshly, the way of the sea, and the other side of the Jordan, the attraction of the nations.
Within the context of chapters 7 and 8 of Isaiah, the Prophet is discussing the 2 waves of exile as a result of the Assyrian Empire. Here the first one (exile of Northern Israel) is mentioned as “mild”, being that the second wave (of Southern Israel, also known as Judah) ALTHOUGH NOT A COMPLETE EXILE, would be much harsher. Knowing the context of chapter 7 and 8 is important as we find the Prophet initially speaking to King Ahaz because of his fear of having his kingdom thwarted by the Assyrians who allied with Northern Israel to go against Judah. (They allied but eventually Assyria would also drive out the Northern Israel).
And you shall say to him, "Feel secure and calm yourself, do not fear, and let your heart not be faint because of these two smoking stubs of firebrands, because of the raging anger of Rezin and Aram and the son of Remaliah. (Isaiah 7:4)
The reason God even is telling Isaiah to speak to Ahaz is due to the promise He made with King David, that the Davidic Dynasty would not be abrogated (even though Ahaz did not merit this). Therefore in Isaiah chapter 7, it is clear that a particular individual would be the vehicle in which God would use to save Ahaz and Judah (Judah being the loyal branch and the remnant of the Davidic covenant, this individual is Hezekiah who WAS righteous and faithful to God and to the Davidic dynasty). What we see at the END of Isaiah 8 is that even though it seems that God’s promise is not being fulfilled and the kingdom of Assyria WILL come to exile part of Judah, eventually OUT OF NO WHERE, they will cease attacking Judah and leave. (This happened in 2 Chronicles 32). The beginning of Isaiah 9 denotes an “interruption” in time from the first wave of exile to now discuss the second wave and how salvation will miraculously come.
BUT, the older christian church did NOT approve of this message. They wanted to fit their theology into this prophecy and make it about an EVEN FURTHER IN THE FUTURE salvation (so that it wouldn’t be within Ahaz’s lifetime):
(Isaiah 9:1) But there will be no more gloom for her who was in anguish. In earlier times He treated the land of Zebulun and the land of Naphtali with contempt, but later on He will make it glorious, by the way of the sea, on the other side of the Jordan, Galilee of the Gentiles. (2) The people who walk in darkness will see a great light;
Those who live in a dark land,
The light will shine on them. (christian translation)
From here, the clear interruption of time is now hidden and it may even seem as though that the ENTIRE chapter 9 speaks in FUTURE TENSE. To prove that this is a deceitful manipulation, compare YOURSELF Isaiah 9:6 (any christian translation) to Isaiah 9:5 from Chabad or any Tanach. NOTICE THE DIFFERENCE BETWEEN THE FUTURE TENSE AND PAST TENSE.
It was not enough to put 8:23 in front of 9:1, they even went as far as CHANGING the tense of the verbiage used to mask this deceit.
The answer: It is clear and obvious, for example, that ‘vayikra’ is not future tense. It should be noted that Isaiah chapter 7 also speaks of the birth of a child whom BEFORE he matures into bar mitzvah age (knowing to choose good and reject evil) the two kingdoms that go against Ahaz will perish:
For, when the lad does not yet know to reject bad and choose good, the land whose two kings you dread, shall be abandoned." (Isaiah 7:16)
Therefore this child, ALREADY WAS BORN (during the first period of time of Isaiah 7 and 8) and only during the period of chapter 9 did the child finally reach the age close to maturity. Proving this DOES NOT correlate to the prophecy of jesus who was approximately born 500-700 YEARS after Isaiah passed away, which would bear no significance to King Ahaz either..
I hope this has been clear, unfortunately this tactic of deception is the same used by christian missionaries to hide the truth and beauty of Tanach. Thank you for your question and for taking the time to read this.