1:1. Paul. In his letters, the apostle never calls himself by his Hebrew name - Saul. Was it to show the break from his former life as Saul, the Pharisee, who tried to destroy the Church?
“Doulos”. The primary meaning of this Greek word is ‘slave’. In the Old Testament, it refers to the one who serves God (Is 49:3.5 LXX). Septuagint uses another word for ‘servant - pais’, of which primary meaning is ’boy/ girl“ (see Is 42:1 LXX; Luke 7:7; 8:54). In Luke 1:38, Mary calls herself ”doulos" of the Lord.
“Apostle”, means messenger. ! The one, who was once a messenger of the High Priest (Acts 9:2), now is a messenger of Christ !
“Separated or set apart”. In Septuagint, the word is used in separating holy things from ordinary ones (Ex 29:27) and pure from impure (Lev 20:25). In the case of Paul, he was set apart - from any other possible way of life - for the “Gospel of God”. That was the point of his Damascus experience.
1:2. The Gospel of God was promised beforehand by God Himself in the holy Scriptures. The word “prophets” can also refer to other figures of the Old Testament (Abraham - Gen 20:7; Moses - Deut 34:10), not just the famous writers of the prophetic books. Thus, God’s Gospel was in God’s plan long before the Gospel was actually proclaimed by the Church / the apostles / Paul.
God’s Son Jesus Christ our Lord. God’s Son has two ‘dimensions’:
1:5. We have already known what is the content of the Gospel, now Paul tells us what is the aim of the Gospel, to bring to the obedience of faith all the nations on behalf of Christ’s name. In the Old Testament, the primarily example of the obedience of faith is Abraham and in the New Testament, Mary.
Paul also explains that preaching the Gospel is a grace. One has to be separated for such task, called from “mother’s womb” (Gal 1:15). It is not based on any merits - after all Paul persecuted the Church - and it cannot be decided by our own wills.
Yet, preaching of the Gospel is also an apostleship, namely an office and dignity of someone being sent by Christ to do such a mission: to bring to the obedience of faith all the nations on behalf of Christ.
1:6–7. The members of the Roman church are among those being already brought to the obedience of faith. Paul uses here the same word “called”, which he used for himself in 1:1. Paul was called an apostle, they are “called of Jesus Christ”. What is the difference? The calling of Paul was into an office of apostleship; their calling was into the obedience of faith. Yet, both calls come from the Son of God.
Aside from being “called of Jesus Christ”, they are also “beloved of God”. This is a profound statement. The same word is used in Mark 1:12, where Jesus is called “beloved” Son of God (see Rom 5:8).
As in 1 Thessalonians (1:2–8), Paul thanks God for their faith that is spoken of in the whole world. (Slight exaggeration? Depending how Paul understood the phrase “the whole world”. His whole world?)
Then, he express his great desire to come and visit them. Here, the reason for his planned visit is to (1) strengthen their faith (1:11); (2) mutual encouragement in faith - Paul also needs it (1:9); (3) finding some opportunity to preach the gospel there (1:13).
The Jews divided the people of the world into two groups: the Jews and the rest - the Gentiles. However, a Hellenistic Jew, could still divide the non-Jews into the Greeks and the barbarians - those, who lived beyond the influence of the Greek culture. The “wise” and the “foolish” probably refers to educated - the philosophers? (Acts 17:18–21), and the uneducated, those who could not afford time and money for education (1 Cor 1:26).
What does it mean that he is debtor to both groups? It means responsibility to preach the Gospel (see 1 Cor 9:16). He will ’pay off the debt", when he will complete his apostleship (2 Tim 4:6–8).
Although, he is ready to preach the Gospel to anybody, including the Romans - it is God who decides the place and the time (see Acts 16:6–7).