First off, it reads as if it had been an afterthought on Paul's part. He ends with this...
Rom. 16:24 The grace of our Lord Jesus Christ be with you all. Amen.
But then adds this...
Rom. 16:25 Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began, 16:26 But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith: 16:27 To God only wise, be glory through Jesus Christ for ever. Amen.
Anyway, that is another topic. In verse 25 he writes "Now to him who is of power to stablish you according to my gospel..."
In other words, in line with "that gospel that I preach among the Gentiles" Gal. 2:2.
There is a lot there also, but lets move on for now.
He uses the phrase "is of power to stablish you according to my gospel..."
One key is in the word "stablish."
Another is in the phrase "according to my gospel."
This gospel that Paul preached among the Gentiles was not mere words.
Its words contained power within them.
Not only the power to "save them that believe" said words - 1Cor 1:21 For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe.
And that right there - how that works - is also a great study in itself.
But also, this gospel that Paul preached among the Gentiles had the power to stablish the Believer.
I say had, but I also mean has, by the way.
What's this about "stablish"? And how does that work?
Paul has already mentioned these two aspects in Romans - its salvation aspect, for example, prior to and into Romans 5:1 Therefore being justified by faith, we have peace with God through our Lord Jesus Christ:
And its stablising aspect in Romans 5:2 going forward...
Rom 5:2 By whom also we have access by faith into this grace wherein we stand, and rejoice in hope of the glory of God.
Which is where he begins to lay out various aspects of living out the Christian life and how to rely on the teaching for that.
He does the same, for example, in...
Col 2:6 As ye have therefore received Christ Jesus the Lord, so walk ye in him:
How did you receive Him? By faith.
How are you to walk in Him? By faith.
Towards what end, and on what basis? That you end up ...
2:7 Rooted and built up in him, and stablished in the faith, as ye have been taught, abounding therein with thanksgiving.
In Col. 2:7, the phrase "Rooted and built up in him" is the same as "stablished in the faith."
As when Scripture reads "God and our Father," Gal. 4:1. He is both to us.
God is "of power to stablish" the Believer how? "According to" Paul's "my gospel."
It is not only able to save one who Believes, but is also able to work in him to conform him to the image of His Son.
It is able to this because that is the power God predetermined it would be able to do, because this is what God predetermined as to how He would one day bring this about in those who trusted His Son....
Rom. 8:29 For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren.
Here all that is again...
1Thess. 2:13 For this cause also thank we God without ceasing, because, when ye received the word of God which ye heard of us, ye received it not as the word of men, but as it is in truth, the word of God, which effectually worketh also in you that believe.
Notice the result that is able to result in, in the Believer...
1Thess. 2:14 For ye, brethren, became followers of the churches of God which in Judaea are in Christ Jesus: for ye also have suffered like things of your own countrymen, even as they have of the Jews:
See that, it stablished them in the faith such that they were enabled by that stablishing to endure persecutions.
This is Romans 5 teaching...
Rom. 5:1 Therefore being justified by faith, we have peace with God through our Lord Jesus Christ: 5:2 By whom also we have access by faith into this grace wherein we stand, and rejoice in hope of the glory of God. 5:3 And not only so, but we glory in tribulations also: knowing that tribulation worketh patience; 5:4 And patience, experience; and experience, hope: 5:5 And hope maketh not ashamed; because the love of God is shed abroad in our hearts by the Holy Ghost which is given unto us.
And not only is that not even a mere a glimpse of all this "grace that is in Christ Jesus" but, we also haven't even gotten into what all else Paul is talking about there, at the end of Romans 16, yet.
Til then study these things out that you might...
2Tim. 2:1 Thou therefore, my son, be strong in the grace that is in Christ Jesus.
Lol - not the "my son" part, that was Timothy, in that case.