Which he had promised afore - Both in the law and in the prophets God showed his purpose to introduce into the world a more perfect and glorious state of things; which state was to take place by and under the influence of the Messiah, who should bring life and immortality to light by his Gospel.
Which he had promised afore - Which gospel, or which doctrines, he had before announced.
By the prophets - The word “prophets” here is used to include those who wrote as well as those who spake. It included the teachers of the ancient Jews generally.
In the holy scriptures - In the writings of the Old Testament. They were called holy because they were inspired by the Holy Spirit, and were regarded as separated from all other writings, and worthy of all reverence. The apostle here declares that he was not about to advance anything new. His doctrines were in accordance with the acknowledged oracles of God. Though they might appear to be new, yet he regarded the gospel as entirely consistent with all that had been declared in the Jewish dispensation; and not only consistent, but as actually promised there. He affirms, therefore:
(1) That all this was promised, and no small part of the Epistle is employed to show this.
(2) that it was confirmed by the authority of holy and inspired men.
(3) that it depended on no vague and loose tradition, but was recorded, so that people might examine for themselves.
The reason why the apostle was so anxious to show that his doctrine coincided with the Old Testament was because the church at Rome was made up in part of Jews. He wished to show them, and the remainder of his countrymen, that the Christian religion was built on the foundation of their prophets, and their acknowledged writings. So doing, he would disarm their prejudice, and furnish a proof of the truth of religion. It was a constant position with the apostle that he advanced nothing but what was maintained by the best and holiest men of the nation. Acts 26:22-23, “saying none other things than those which the prophets and Moses did say should come,” etc. There was a further reason here for his appealing so much to the Old Testament. He had never been at Rome. He was therefore personally a stranger, and it was proper for him then especially to show his regard for the doctrines of the prophets. Hence, he appeals here so often to the Old Testament; and defends every point by the authority of the Bible. The particular passages of the Old Testament on which he relied will come before us in the course of the Epistle. See particularly Romans 3; 4; 9; 10; 11. We may see here,
(1)The reverence which Paul showed for the Old Testament. He never undervalued it. He never regarded it as obsolete, or useless. He manifestly studied it; and never fell into the impious opinion that the Old Testament is of little value.
(2)if these things were promised - predicted in the Old Testament, then Christianity is true. Every passage which he adduces is therefore proof that it is from God.