17 But if some of the branches were broken off, and you, being a wild olive, were grafted in among them and became partaker with them of the [h]rich root of the olive tree, 18 do not be arrogant toward the branches; but if you are arrogant, remember that it is not you who supports the root, but the root supports you. 19 You will say then, “Branches were broken off so that I might be grafted in.” 20 Quite right, they were broken off for their unbelief, but you stand by your faith. Do not be conceited, but fear; 21 for if God did not spare the natural branches, He will not spare you, either. 22 Behold then the kindness and severity of God; to those who fell, severity, but to you, God’s kindness, if you continue in His kindness; otherwise you also will be cut off. 23 And they also, if they do not continue in their unbelief, will be grafted in, for God is able to graft them in again. 24 For if you were cut off from what is by nature a wild olive tree, and were grafted contrary to nature into a cultivated olive tree, how much more will these who are the natural branches be grafted into their own olive tree?
25 For I do not want you, brethren, to be uninformed of this mystery—so that you will not be wise in your own estimation—that a partial hardening has happened to Israel until the fullness of the Gentiles has come in; 26 and so all Israel will be saved; just as it is written,
“The Deliverer will come from Zion,
He will remove ungodliness from Jacob.”
27 “This is My covenant with them,
When I take away their sins.”
28 From the standpoint of the gospel they are enemies for your sake, but [k]from the standpoint of God’s choice they are beloved for the sake of the fathers; 29 for the gifts and the calling of God are irrevocable. 30 For just as you once were disobedient to God, but now have been shown mercy because of their disobedience, 31 so these also now have been disobedient, that because of the mercy shown to you they also may now be shown mercy. 32** For God has shut up all in disobedience so that He may show mercy to all.**
33 Oh, the depth of the riches both of the wisdom and knowledge of God! How unsearchable are His judgments and unfathomable His ways! 34 For who has known the mind of the Lord, or who became His counselor? 35 Or who has first given to Him [m]that it might be paid back to him again? 36 For from Him and through Him and to Him are all things. To Him be the glory [n]forever. Amen.
I think Paul demonstrates in this portion, some things he states elsewhere(Eph 1:9-11, 1 Cor 15:22-28, Phil 2:9-11)- but uniquely here from the perspective of Israel’s correction and restoration.
In a sense Paul is using the way in which the Lord has dealt with Israel as an example of how He has dealt with all mankind. So in this I think the words from Jeremiah are very strong in a biblical universalist’s view.
Similarly, in Roman’s 8 there is a glimpse of this same method in which God has chosen to enlighten all men and eventually unify them with Himself through Jesus Christ.
Rom 8:18 For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us. 19 For the anxious longing of the creation waits eagerly for the revealing of the sons of God. **For the creation was subjected to futility, not willingly, but because of Him who subjected it, in hope that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. **22 For we know that the whole creation groans and suffers the pains of childbirth together until now. 23 And not only this, but also we ourselves, having the first fruits of the Spirit, even we ourselves groan within ourselves, waiting eagerly for our adoption as sons, the redemption of our body. 24 For in hope we have been saved, but hope that is seen is not hope; for who hopes for what he already sees? 25 But if we hope for what we do not see, with perseverance we wait eagerly for it.