“By oracles he means the covenant which God revealed first to Abraham and to his posterity, and afterwards sealed and unfolded by the law and the Prophets.
Now the oracles were committed to them, for the purpose of preserving them as long as it pleased the Lord to continue his glory among them, and then of publishing them during the time of their stewardship through the whole world: they were first depositories, and secondly dispensers. But if this benefit was to be so highly esteemed when the Lord favored one nation only with the revelation of his word, we can never sufficiently reprobate our ingratitude, who receive his word with so much negligence or with so much carelessness, not to say disdain.”
~John Calvin, Commentary on Romans, Ch. 3