Romans 11:28-36
Rom 11:28 (KJV)
As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the fathers' sakes.

Paul now turns to the Gospel and tells them that Israel was the enemy of the Gospel. This is because they did not embrace the gospel of grace because they believed their salvation was secured by the keeping of the law. They did not understand that the truth of the Gospel came through the person of the Lord Jesus Christ. As enemies of the Gospel, God had broken them off as the branches so the Gentiles could be grafted in. Then Paul speaks of the election according to grace, which they are beloved because God had promised that He would save a remnant of Israel by Grace, which was according to the eternal covenants that He promised to Abraham and confirmed through Isaac and Jacob.

Rom 11:29 (KJV)
For the gifts and calling of God are without repentance.

The word “repentance” in the Greek carries with it the meaning of “irrevocable.“ When God calls someone and grants them the gift of salvation, He does not change His mind and remove it for the slightest infraction. Here Paul is also alluding to the fact that God was calling and saving many Gentiles and the giving of salvation would not be rescinded, even while God was saving a remnant from Israel.

Rom 11:30 (KJV)
For as ye in times past have not believed God, yet have now obtained mercy through their unbelief:

In the past the Gentiles were mainly idol worshippers and caught up in the false religions. Now, God is grafting them into the Kingdom of God through the Lord Jesus Christ. This influx of saved Gentiles was the result of obtaining mercy because of the unbelief of Israel. These Gentiles will be coming into the Kingdom from every country in the world right up until the last day.

Rom 11:31 (KJV)
Even so have these also now not believed, that through your mercy they also may obtain mercy.

Now because they have not believed the true Gospel but the Gentiles that have been coming into the Kingdom of God, are now able to show mercy to those Israelites by bringing them the Gospel. The Gentiles should not cut themselves off from the Jews but instead should be bringing them the Gospel so that the remnant of believers will continue to come out of darkness and be placed back into the tree in their natural environment.

Rom 11:32 (KJV)
For God hath concluded them all in unbelief, that he might have mercy upon all.

Here is one of those verses which must be looked at carefully. The word “concluded” in the Greek carries with it the meaning of “enclose or consign.” So we see that God has consigned the nation of Israel to unbelief. Then Paul goes on to say that God will have mercy upon all. Now He is not speaking of the entire nation of Israel because God has never saved an entire nation. His salvation plan is initiated one person at a time. God is going to have mercy on those that believe the Gospel.
(Gal 3:22 KJV) But the scripture hath concluded all under sin, that the promise by faith of Jesus Christ might be given to them that believe. This is confirmed in the Galatians verse that we see that all are under sin but the promise of Faith is given to them believe. If you notice, it says that the promise is given and not asked for as in a free will Gospel.

Rom 11:33 (KJV)
O the depth of the riches both of the wisdom and knowledge of God! how unsearchable are his judgments, and his ways past finding out!

This epilogue is telling us that the riches of the wisdom and knowledge of God are very deep and that depth is absolutely unreachable by any finite person. The one who thinks that they can understand the ways of God will be deluded about other things as well. The words “finding out” in the Greek, carry with it the meaning of “untraceable, incomprehensible, and cannot be explored.” The word “unreachable” carries with it the meaning of “inscrutable.” Inscrutable means “not readily investigated, interpreted, or readily understood.”

Rom 11:34 (KJV)
For who hath known the mind of the Lord? or who hath been his counsellor?

What human being on this earth could actually know the mind of the Lord. What finite being could be His equal to the point that they are able to counsel Him? Those who are saved are given the mind of Christ but while we are in these physical bodies, we will never have the full capacity of that mind. Even when we are in glory, our knowledge and understanding will never be equal to that of the Lord’s.

Rom 11:35 (KJV)
Or who hath first given to him, and it shall be recompensed unto him again?

(1 John 4:19 KJV) We love him, because he first loved us. No saved person on Earth has initiated their salvation. God is the one who has given salvation to a person. God is also the one who has given all the common gifts on this Earth to the entire human race. God gives the sun, He gives the rain, He gives the harvest, He gives us our families, etc. There is nothing that we have not received from God. (1 Cor 4:7 KJV) For who maketh thee to differ from another? and what hast thou that thou didst not receive? now if thou didst receive it, why dost thou glory, as if thou hadst not received it? This principle is confirmed in 1 Corinthians 4:7, that it is God who has given all things and all we did was receive them. Therefore, it follows that God will not have to repay anything to any human being since everything we have initially came from God Himself.

Rom 11:36 (KJV)
For of him, and through him, and to him, are all things: to whom be glory for ever. Amen.

God is the recipient of all the glory. No person can boast of anything they have. There is no such thing as a self-made millionaire. Were they able to create themselves? We as believers have received salvation from God, through Christ, and for Him. God is the source, the agency of administration of all things, and the definitive end of all things.