Although Paul grieves for corporate ethnic Israel because they are cut off from Christ in spite of all the saving privileges that belong to them
Nevertheless , the Word of God has not fallen
First Phase of Paul's Argument (the Divine side) : God never intended to save every ethnic Israelite. For not all ethnic Israel is true Israel, only the children of promise are true Israel. For God elects apart from any human distinctive
And He is righteous in doing so because His righteousness is manifested in His sovereign freedom to elect apart from any human distinctives.
He is righteous also because God’s purpose in doing so is to display his power, to proclaim His Name and ultimately to make known the riches of His glory upon vessels of mercy
God calls vessels of mercy not only from among Jews but also from among Gentiles.
Second Phase of Paul's Argument (the human side of Israel's failure to be saved) : Though Gentiles have obtained righteousness by faith, Israel did not.
The reason Israel has not obtained salvation (and Paul prays for them) is because in their misguided zeal they sought to establish their own righteousness, refusing to submit to God's righteousness in Christ which is by faith and not by works of the Law
For Moses himself gives evidence that this righteousness comes not through obedience to the covenant at Sinai but through faith in Christ resulting from the New Covenant
Ample evidence in the Writings and the Prophets also make clear that corporate ethnic Israel has culpably and stubbornly refused to respond to the gospel of free grace while Gentiles have found it.
Third Phase of Paul's Argument : In spite of Israel's rejection of God's righteousness in Christ, God has not rejected corporate ethnic Israel whom He has foreknew
For He has always preserved and is continuing to preserve a remnant of corporate ethnic Israel even though He has hardened (for a season) the majority of corporate ethnic Israel
Fourth Phase of Paul's Argument : corporate ethnic Israel did not stumble in order to utterly fall but rather in order to bring salvation to the Gentiles and then ultimately to be saved themselves
For corporate ethnic Israel is indeed holy (set apart for God's possession) with the result that you, Gentiles, should never boast over their being cut off
Therefore God will graft them in again and save all corporate ethnic Israel when the purpose of their hardening has been accomplished and the Deliverer will come from Zion and banish their ungodliness
Paul's response to God's sovereign round-about way of accomplishing His Word is to be awestruck and to render God all glory, the One from Whom and through Whom and to Whom are all things