Commentaries:
Paul extends the meaning of oracles here in two ways—in content and audience:
The content of the message includes the entire Law. Since the general context is circumcision (see chapter 2), we can conclude that the oracles given to the fathers included the covenants and hence the promises that attended them. The context does not limit the oracles to the revelation of God in the Pentateuch, but can include the Writings and Prophets as well.
The audience of the message includes those outside national Israel. Just before he writes of the oracles being committed to the Jews, Paul informs us that "he is not a Jew, who is one outwardly; . . . but he is a Jew, who is one inwardly" (Romans 2:28-29). Paul is speaking of the "Israel of God" (Galatians 6:16). In this regard, Peter makes an instructive statement in his conversation with the gentile Cornelius:
The word [logos] which God sent to the children of Israel, preaching peace by Jesus Christ—He is Lord of all—that word you know, which was proclaimed throughout all Judea, and began from Galilee after the baptism which John [the Baptist] preached. (Acts 10:36-37)
Peter came to recognize that the oracles of God are for all men, God showing "no partiality" (verse 34).
Charles Whitaker
The Oracles of God