You're adding to the text. Show me the words "Son of God" in Job.
The statute is eternal, we simply don't have a temple.
The existance of Messianic Jews is irrelevant to whether or not the New Covenant annuls the Old Covenant.
Sure it does.
Deuteronomy 4:2. "... do not add or remove ... "
In Job 9: 32-35 he said, "If only there were someone to mediate between us, someone to bring us together, someone to remove God’s rod from me, so that his terror would frighten me no more. Then I would speak up without fear of him, but as it now stands with me, I cannot." That is a reference to the Messiah. There was a reason God mentioned that verse because God is not the author of confusion. That verse is a clear reference to the Messiah.
The existence of Messianic Jews are relevant because the New Covenant doesn't annul the New Covenant.
Deuteronomy 4:2 says not to add to the Bible, but the other books of the Tanakh are additional writings. They don't add to the Bible because they have an order and a purpose. The same applies to the New Covenant of the Messiah.