His kinsman according to the flesh were promised a Messiah who would save them from their sins. They rejected Christ and so were cut off from the promise of God.
Make sure you look at all the words of those verses. Both physical and spiritual is in view.
"to the end the promise might be sure to all the seed;
not to that only which is of the law, but to that also which is of the faith of Abraham"
And while we are in Romans, don't forget to study chapters 9, 10, and 11 which includes this little morsel:
Romans 11:28-29 (NKJV) Concerning the gospel they are enemies for your sake, but concerning the election they are beloved for the sake of the fathers. 29
For the gifts and the calling of God are irrevocable.
You have to keep in mind, the covenant that God made with Abraham and his descendants regarding physical land and such, was an unconditional covenant. Study what went on when God performed the ceremony of sealing the covenant in Genesis 15:7-21.
In a covenant sealing ceremony in ancient times, when two parties sealed a covenant, animals are cut in two and the two parties pass thru them reciting the words of the covenant, that if either break the covenant, they will be as those cut animals. God caused a deep sleep to fall over Abraham, and God Himself passed thru the cut animals, signifying that the covenant was dependent only on God to maintain. Abraham and his physical descendants couldn't break the covenant if they wanted to. God enforces the covenant and will not break it, or His word is on the line. If the covenant is broken, then God is a liar. And God holds nothing higher than His word.
And if God's word isn't good enough to uphold the covenant, then His word is not good enough to uphold your salvation. God is one who delights in making and keeping His promises. His character and word is on the line. Every true believer relies on God's promises. If they cannot be relied upon, then this whole Christianity thing is worthless.
Sure, Israel was dispersed from the land due to rebellion, but the promise is still valid. And the period of time that God specified that they would be punished has come to an end. Israel, as per the prophecies, is in the land. Sure, initially in unbelief. Like dry bones as stated in Ezekiel 37. But God will breath life back into them. But it will take the tribulation period to finally wake them up and then the prophesy in Hosea will be realized fully:
Hosea 5:15-6:2 (NKJV) I will return again to My place
Till they acknowledge their offense.
Then they will seek My face;
In their affliction they will earnestly seek Me.”
Chapter 6
1 Come, and let us return to the Lord;
For He has torn, but He will heal us;
He has stricken, but He will bind us up.
2 After two days He will revive us;
On the third day He will raise us up,
That we may live in His sight.
For God to return to His place, He had to have left it. And He did, as Messiah who was crucified, buried, and resurrected. And Messiah had this passage in Hosea clearly in mind when He stated:
Matthew 23:38-39 (NKJV) See! Your house is left to you desolate; 39 for I say to you, you shall see Me no more till you say, ‘Blessed is He who comes in the name of the Lord!’ ”