Rom 15:8 Now I say that Jesus Christ was a minister of the circumcision for the truth of God, to confirm the promises made unto the fathers: Rom 15:9 And that the Gentiles might glorify God for his mercy; as it is written, For this cause I will confess to thee among the Gentiles, and sing unto thy name.
Rom 15:10 And again he saith, Rejoice, ye Gentiles, with his people.
Rom 4:13 For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith.
Rom 4:14 For if they which are of the law be heirs, faith is made void, and the promise made of none effect:
Rom 4:15 Because the law worketh wrath: for where no law is, there is no transgression.
Rom 4:16 Therefore it is of faith, that it might be by grace; 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; who is the father of us all,
Rom 4:17 (As it is written, I have made thee a father of many nations,) before him whom he believed, even God, who quickeneth the dead, and calleth those things which be not as though they were.
Rom 4:18 Who against hope believed in hope, that he might become the father of many nations, according to that which was spoken, So shall thy seed be.
Rom 4:19 And being not weak in faith, he considered not his own body now dead, when he was about an hundred years old, neither yet the deadness of Sara's womb:
Rom 4:20 He staggered not at the promise of God through unbelief; but was strong in faith, giving glory to God;
Rom 4:21 And being fully persuaded that, what he had promised, he was able also to perform.
Rom 4:22 And therefore it was imputed to him for righteousness.
Rom 4:23 Now it was not written for his sake alone, that it was imputed to him;
Rom 4:24 But for us also, to whom it shall be imputed, if we believe on him that raised up Jesus our Lord from the dead;
Rom 4:25 Who was delivered for our offences, and was raised again for our justification.
All the one gospel..
LA
Romans 9-11, summarized in Rom. 11:25-29, relates that Rom. 15:8-12 was interrupted.
Thus 15:13's
"Now the God of hope..." was superseded by 13 thru 21 via an Apostle of the Gentiles.
Rom. 15:8-12 was Prophesied and foresees Israel redeemed first - at the 2nd Coming, and then the Gentiles, Isaiah 60: 2-3. It is Acts 3:25-26's "unto you first." Peter also relates in 2 Peter 3 that that was interrupted per what Paul wrote about that, 2 Peter 3: 14-15.
Romans 11 relates that "through their fall salvation is come unto the Gentiles."
Note, not through Israel's prophesied rise, that one is on hold.
Rather through their fall.
An the word in Rom. 15:8 is "promises" - plural, not singular. That is this here - Romans 9:
4. Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises;
5. Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen.
Romans 15:8-12 is the so called "Great Commission" that began in Matthew 10 and was prophesied in Matt. 10:23 would not be completed "til the Son of man be come."
Romans 11:25 relates "this mystery" that during God's having put that on hold - during Israel's fall - He is visiting the Gentiles directly, rather than, as prophesied; through Israel's rise.
And this post should confuse the heck out of you as it is a perspective you are not familiar with.
In Romans...11:25-29 relates that 1Rom. 5:8-12, which was prophesied, is on hold, and that now the God of hope is working Rom. 15:13-21.
Romans 15:8-12 is Acts 15:16's "After this, I will return and build again the tabernacle of David," etc.