The church at Rome is composed of all who are in the Body of Christ. Paul was addressing all that be in Rome, "all", no one exempted nor left out;Rom 8:32
He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things?
Now what about this scripture? Who are the all Christ was delivered up for? Was it all mankind? No it is not! It's for all the Church, the Elect Vs33;It means all the Church, Paul was addressing the Church at Rome, the beloved of God, called to be Saints, of whom He had heard of their Faith Rom1:6-8
6 Among whom are ye also the called of Jesus Christ:
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.
8 First, I thank my God through Jesus Christ for you all, that your faith is spoken of throughout the whole world.
He was addressing all that be in Rome, beloved of God, for God so loved the world and the Church is the Body of Christ.
And who are in the Body of Christ?
God saved Adam that same day he fell into sin, an act that cost the Father His only begotten Son - the Lamb slain from the foundation of the world. And God saved Adam through Christ for no other name under heaven was given for the salvation of man. With Adam in Christ, all his descendants are born in Christ! Being in Christ, they are in His Body and hence comprise the Church the Bible speaks of.