Chizuk Emunah (Pt 2) Under the Microscope: Chapter 81

Romans 11:26, "And so all Israel shall be saved, as it is written, There shall come out of Zion the deliverer, and shall turn away ungodliness from Jacob."

The true words of the prophet (Isaiah 59:20), do not indicate that the Messiah will turn away ungodliness from Jacob, but that "a redeemer will come to Zion, and to those who return from transgression in Jacob, saith the Lord." 

ἥξει ἕνεκεν Σιων ὁ ῥυόμενος καὶ ἀποστρέψει ἀσεβείας ἀπὸ Ιακωβ  (Isaiah 59:20)

Ἥξει ἐκ Σιὼν ὁ ῥυόμενος καὶ ἀποστρέψει ἀσεβείας ἀπὸ Ἰακώβ (Romans 11:26)

Again, Paul simply quotes the Septuagint almost verbatim. The word at the beginning, whether it be
ἐκ (from) or ἕνεκεν (for the sake of) is immaterial to addressing Troki's argument. The Septuagint does say that Messiah will turn ungodliness away from Jacob. I have already written extensively on the reliability of the Septuagint, as well as the fact that it long predates the church.

In fact, Emanuel Tov has argued in Textual Criticism of the Hebrew Bible that most of the Tanakh was translated into Greek before the era of the Maccabees.

Furthermore, the Targum agrees with the Septuagint's reading, which states that the redeemer will "bring back the rebelliousnesses of the House of Jacob to the Law."