In Isaiah 9:7 we have an oddity we have לםרבה (lemabeh) meaning "of his increase" now, anyone who knows Hebrew, can see something is not right here. The thing that is out of place is the מ which is written as ם now the מ is written as ם if it is the last letter of a word. Never ever at the beginning or middle. We have several letters that have a beginning and ending form. They are known as otyiot sofit. So as we can see the scroll should properly read, למרבה as opposed to לםרבה.
With the Masoretic text which is the standardized text in Judaism there is a commentary within the text through broken letters, misspelled words, letters added or missing, letters bigger or smaller etc. This was to retain the original meaning of the verse. Now, after a long search through the Talmud I have found that the only time a ם sofit is mentioned is in Shabbat 104a-104b. No where else. So now I have to jump to the medieval times and Rashi. And Rashi says that the "Wonderful Counselor" mentioned in verse 6 is speaking of Mashiach, but he attributes Mashiach to Hezekiah. Then he kinda backs away from the thought that Hezekiah is Messiah and lists the reasons he couldn't be.
Now the Targums, translate this verse not as G-d but as Mashiach, and the Targum of Jonathan is also a standardized Jewish text. So this concept was there and understood at this time. And it is not a "Christian invention" as the anti-missionaries claim that the Messiah was born of a virgin signifying a womb that is closed in the first coming of Mashiach where the word Almah is used.
But we also have to have a second testimony of this. And it comes from the book of Nehemiah. And in Nehemiah 2:13 we see הפרוצימ which should read הפרוצים (perotzim) meaning "broken one" signifies Mashiach coming to repairs that final mem to make it ם through his previous brokenness. And Radak, the great sage connects the two and says that the Messiah will appear when the walls of Jerusalem are sealed through tikkun from within the wall and he relates this to Amos 9:11 when it says "in that day will I raise up the tabernacle of David that is fallen and close the breaches there of (ם) and I will raise up his ruins, and I will build it as in the days of old."
Now this carries on over into an unlikely of places, Sukkah 52a of the Talmud which is making note of verses about the Mashiach in Zechariah, but we see the premise is there, not only of two Messiah's but also the interpretation of Radak and the reason for Mashiach through our own internal issues with the Yetzer Hara. I have scanned Sukkah 52a in it's entirety for you to see for yourself:
Ok so you maybe saying to yourself. "well obviously Judaism taught about 2 comings of Messiah or 2 Messiah's but what is this Evil Inclination business?" That is one of the big keys to the parallel of Radak's words. Because to bring tikkun one has to defeat the evil inclination (yetzer hara), so the attributes of Mashiach Ben Yosef, break us, and humble us, and the attributes of Mashiach ben David put it into action in confidence that is properly allocated within the soul. Therefore, the thought pattern from the Talmud about another verse about the Messiah from Zechariah carried many many many years later in an unbroken halakha to Radak.
Theological Insights from Rabbi Eved Banah the North American Rebbe of Ani Judaism