Romans 3:1-2 — What advantage then hath the Jew? or what profit is there of circumcision?
Much every way: chiefly, because that unto them were committed the oracles of God.
The opening question is saying "What is the advantage of being a Jew if Jews are lumped with heathens in guilt?" It's a follow-up to Paul's conclusions in chapter 2.
The Jews were entrusted with the reception, inscription and transmission of God's Word. Other advantages are mentioned in Romans 9:4-5 — Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises; whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen.
Oracles = utterances = the Law and other revelation in the Old Testament and the right to worship God that went along with it.