Romans 1:14

Debtor [ο φ ε ι λ ε τ η ς]. All men, without distinction of nation or culture, are Paul's creditors, "He owes them his life, his person, in virtue of the grace bestowed upon him, and of the office which he has received." (Godet).

Greeks - Barbarians. Gentiles without distinction. Paul takes the conventional Greek division of all mankind into Greeks and non - Greeks. See on Acts 6:1. The question whether he includes the Romans among the Greeks or the Barbarians, is irrelevant.