Romans 11:27

For this is my covenant unto them, when I shall take away their sins.

God's covenant to Israel is that He will take away their sins. That covenant is fulfilled through the Deliverer coming out of Sion to turn away ungodliness from Jacob. Blindness in part has happened to Israel until the fulness of the Gentiles comes in, and then all Israel shall be saved.

The Jews were broken off the olive tree because of unbelief, while Gentile believers as a wild olive tree were grafted in among them to partake of the root and fatness, standing only by faith. Israel as a nation lost her connection with God through unbelief and rejection of Heaven's purpose, while the remnant true to the God of their fathers remains as the true stock. If they abide not still in unbelief, God is able to graft the natural branches into their own olive tree again and reunite the separated branches with the true stock. This happens when the seed of Israel accept Christ and are grafted into Christ Jesus as the true stock, so those broken off and cast away will not remain cast away.

As concerning the gospel they are enemies for the Gentiles' sakes, but as touching the election they are beloved for the fathers' sakes, for the gifts and calling of God are without repentance. As Gentiles who had not believed obtained mercy through Israel's unbelief, so Jews who now believe not may obtain mercy, for God has concluded them all in unbelief that He might have mercy upon all, and He is abundantly able to transform Jew and Gentile and grant every believer in Christ the blessings promised to Israel. Their receiving will be as life from the dead, and their fulness will be far greater riches than their fall.

The covenant will be fulfilled in a mighty work in which the Gentiles are gathered in and the Jews are gathered also, with many Jews everywhere converted and coming to the light of present truth. Through them the salvation of God will go forth as a lamp that burneth as the Lord God works and does wonderful things in righteousness. Among the Jews the Lord has mighty men who will proclaim the truth with power. Many of these converted Jews will come to the light of present truth and proclaim the immutability of God's law with wonderful power. Gentile believers must not despise the Jews nor boast against the branches nor be highminded, but must fear and continue in God's goodness or also be cut off.

The chapter outlines a great work for the Jews that must not be ignored but must be treated with special wisdom, requiring God's wisdom to clear the King's highway in all wisdom and righteousness and giving the Jews every opportunity to come to the light. That work includes giving money and a farm home as a refuge where converted Jews cut off from their people can live and learn how to work for their own people. With the praise of the depth of the riches of the wisdom and knowledge of God, the verse shows God gives great privileges to understand and know His will, to increase in faith and righteousness, and to grow up in Christ the living Head. It calls the church to study Romans 12 and to religious duty where every member does the class of work he is fitted for so all blend in a complete whole, presenting the body a living sacrifice holy and acceptable to God, not conformed to the world but transformed by the renewing of the mind to prove the good and acceptable and perfect will of God, thinking soberly and not more highly of self than ought, according as God has dealt to every man the measure of faith.