>Just as it is written,
>“For Your sake we are being put to death all day long;
>We were considered as sheep to be slaughtered.”
A reference to Psalm 44. The implication being that, no, none of the hardships and troubles that Paul mentioned in the previous verse can separate God from his elect, just as they did not separate God from Israel in the psalm.
>But in all these things we overwhelmingly conquer through Him who loved us.
"We" refers to the same object that "us", which is Paul and his audience in Rome. No change in pronoun object. Through Jesus, the church overcomes death and all hardships.
>For I am convinced that neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers,
>nor height, nor depth, nor any other created thing, will be able to separate us from the love of God, which is in Christ Jesus our Lord.
NONE OF THE THINGS™ can separate us (Paul and his audience in Rome) from the love of God provided through Jesus.
Chapter 9
>I am telling the truth in Christ, I am not lying, my conscience testifies with me in the Holy Spirit,
>that I have great sorrow and unceasing grief in my heart.
What could possibly make Paul so sad?
>For I could wish that I myself were accursed, separated from Christ for the sake of my brethren, my kinsmen according to the flesh,
Paul loves his people, as we all should. However the implication here is that most of his nation is not among those being joined to Christ.
>who are Israelites, to whom belongs the adoption as sons, and the glory and the covenants and the giving of the Law and the temple service and the promises,
>whose are the fathers, and from whom is the Christ according to the flesh, who is over all, God blessed forever. Amen.
>But it is not as though the word of God has failed.
Again, most of national Israel didn't make the cut and are not joined to Jesus. So what's going on?
>For they are not all Israel who are descended from Israel;
Just because you're born of earthly Israel does not mean you're a part of the true Israel.
>nor are they all children because they are Abraham’s descendants, but: “through Isaac your descendants will be named.”
Reference back to Genesis 21:12. Paul is bringing out the fact that God's promise to Abraham included his "seed" being named through Isaac, not merely Jacob. The promise God was making involved something more than just Jacob's biological offspring.
>That is, it is not the children of the flesh who are children of God, but the children of the promise are regarded as descendants.
It's not enough to claim being descended of Abraham or Jacob. That means nothing, spiritually speaking. What made Abraham special was his faith, and the children of the promise, Abraham's true children, are those who live by the same kind of faith that Abraham had.
>For this is the word of promise: “At this time I will come, and Sarah shall have a son.”
Abraham had faith in God's promise, and so Isaac was born.
>And not only this, but there was Rebekah also, when she had conceived twins by one man, our father Isaac;
And Isaac had faith in God's promise to his father, and so Jacob and Esau were born…
>for though the twins were not yet born and had not done anything good or bad, so that God’s purpose according to His choice would stand, not because of works but because of Him who calls,
>it was said to her, “The older will serve the younger.”
>Just as it is written, “Jacob I loved, but Esau I hated.”
Why was Jacob chosen to be greater than his brother? Because God, in his wisdom, decided it was the most fitting way to fulfill his promise to Abraham. It was entirely based on God's purpose for creating Jacob in the first place, not upon anything Jacob or Esau did. God's purpose was always the same for them.