You miss the obvious, DP.
Paul is asserting that he has been separated unto good news from God.
He then identifies Who said good news is about.
The very Core of God's good news Himself.
The Central Figure of said good news.
Who is He?
Who has God's good news always been about?
Who is His good news about even now?
About the same Individual Whom God had Prophesied about.
The same individual Who proved by His resurrection from the dead, had been the very Individual Who had been Prophesied about.
What Paul has done is laid out Christ's Authority.
For what purpose?
Towards proving first, His Authority.
Towards proving through that that it is said Authority Himself Who has both called and separated Paul unto his Appstleship among the Gentiles.
Unto what?
To what intent?
For PAUL'S obedience to The Faith among all nations FOR, or IN His Name.
Now either Paul was preaching Israel's same expected obedience to The Faith among all nations for His Name, or Paul was not.
You within Mid-Acts who assert what you erroneously do about verses 1-4 cannot both disagree with the IP's of the world (their assertion that Paul's had been a continuance of Israel's prophesied and thus expected "mission" obedience), and then turn around and contradict yourselves with this error of yours on Rom. 1:1-4.
All Paul is doing is establishing is the Authority of the Individual Who gave him his authority among the Gentiles.
This two-fold issue - of just Who Christ had actually been; and Who actually gave Paul his authority among the Gentiles - is one Paul often brings up throughout his writings.
Romans 1:1 Paul, a servant of Jesus Christ, called to be an apostle, separated unto the gospel of God, 1:2 (Which he had promised afore by his prophets in the holy scriptures,) 1:3 Concerning his Son Jesus Christ our Lord, which was made of the seed of David according to the flesh; 1:4 And declared to be the Son of God with power, according to the spirit of holiness, by the resurrection from the dead: 1:5 By whom we have received grace and apostleship, for obedience to the faith among all nations, for his name: 1:6 Among whom are ye also the called of Jesus Christ: 1:7 To all that be in Rome, beloved of God, called to be saints: Grace to you and peace from God our Father, and the Lord Jesus Christ.
Here this Two-Fold issue is, again...near the very end of his life...
1 Timothy 1:15 This is a faithful saying, and worthy of all acceptation, that Christ Jesus came into the world to save sinners; of whom I am chief. 1:16 Howbeit for this cause I obtained mercy, that in me first Jesus Christ might shew forth all longsuffering, for a pattern to them which should hereafter believe on him to life everlasting. 1:17 Now unto the King eternal, immortal, invisible, the only wise God, be honour and glory for ever and ever. Amen.
There that authority issue is again.
This PROVEN Authority Himself...
1 Timothy 6:13 I give thee charge in the sight of God, who quickeneth all things, and before Christ Jesus, who before Pontius Pilate witnessed a good confession; 6:14 That thou keep this commandment without spot, unrebukeable, until the appearing of our Lord Jesus Christ: 6:15 Which in his times he shall shew, who is the blessed and only Potentate, the King of kings, and Lord of lords; 6:16 Who only hath immortality, dwelling in the light which no man can approach unto; whom no man hath seen, nor can see: to whom be honour and power everlasting. Amen.
Again, DP, these issues are studied out DOCTRINALLY not via isolated Greek word studies.
The question is "what is the doctrine (teaching) on this, that, or the other?"
It is not "what is the Greek word for this, that, the other?"
Why?
Because it is "in the volume of the book it is written of me" - Hebrews 10:7.
The governing principle of Bible study Isaiah spoke of...
Isaiah 8:20 To the law and to the testimony: if they speak not according to this word, it is because there is no light in them.
And that Paul had reminded Timothy of, in what may have been his last words to a fellow Bible student...
2 Timothy 3:14 But continue thou in the things which thou hast learned and hast been assured of, knowing of whom thou hast learned them; 3:15 And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus. 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: 3:17 That the man of God may be perfect, throughly furnished unto all good works.
Rom. 14:5 towards you, DanP - in memory of Rom. 5: 6-8 - in each our stead - THIS SIDE OF 2 Cor. 5:19.