Rom 1:2

“You the reader must decide whether this is to be understood simply of the gospel which was promised by God through the prophetic Scriptures or whether this is said in order to distinguish it from another gospel, which John calls "eternal" in the book of Revelation. This gospel will be revealed when the shadow passes and the truth comes, when death will be swallowed up and eternity restored. It seems that those eternal years of which the prophet spoke also belong to this eternal gospel: "I had the eternal years in mind."48It must be understood that what was predicted by the prophets concerning Christ was also predicted concerning the gospel, although the Evangelist Mark seems to make a distinction between Christ and the gospel when he says: "Whoever has left father or mother … for my sake or for the gospel." But if promises referring specifically to the gospel are what is required, you will find an abundance of them in the prophets, to wit: "The Lord will give his word with great power to those who preach the good news," and: "How beautiful are the feet of those who bring good news."”

“"Which He promised afore by His Prophets in the Holy Scriptures." For the Lord, saith he, "shall give the word to them that proclaim glad tidings with great power"; and again, "How beautiful are the feet of them that preach the Gospel of peace." See here both the name of the Gospel expressly and the temper of it, laid down in the Old Testament. For, we do not proclaim it by words only, he means, but also by acts done; since neither was it human, but both divine and unspeakable, and transcending all nature. Now since they have laid against it the charge of novelty also, He shows it to be older than the Greeks, and described aforetime in the Prophets. And if He gave it not from the beginning because of those that were unwilling to receive it, still, they that were willing did hear it. "Your father Abraham," He says, "rejoiced to see My day, and he saw it, and was glad." How then comes He to say, Many prophets desired to see the things which ye see, and have not seen them? He means not so, as ye see and hear, the Flesh itself, and the very miracles before your eyes. But let me beg you to look and see what a very long time ago these things were foretold. For when God is about to do openly some great things, He announces them of a long time before, to practise men's hearing for the reception of them when they come. "In the Holy Scriptures." Because the Prophets not only spake, but also writ what they spake; nor did they write only, but also shadowed them forth by actions, as Abraham when he led up Isaac, and Moses when he lifted up the Serpent, and when he spread out his hands against Amalek, and when he offered the Paschal Lamb.”

“Paul preaches no other Christ than the Christ whose gospel the prophets promised would go forth from Jerusalem. He declares that they are prophets of God and that the Scriptures which prophesied about Christ are holy. This entire passage contradicts the Manichaeans, for it says that the gospel was promised beforehand through God's prophets and in the Holy Scriptures and that according to the flesh Christ came from the lineage of David, i.e., from the Virgin Mary, just as Isaiah had foretold.”

“The prophets arose from the Jewish people, and Paul testifies that the gospel, in which believers are justified by faith, had been promised earlier through them.… For there are Gentile prophets as well, in whom also are found some things which they heard of Christ and prophesied. This sort of thing is even said about the Sibyl [Virgil, Eclogues 4.4] … but the writings of the Gentiles, so very full of superstitious idolatry, ought not to be considered holy just because they say something about Christ.”

“Paul says "his prophets" because there are also prophets of idols, and by the word his he distinguishes one type of prophet from another and one gospel from another. For there are many gospels, but they are moral and temporary, whereas that of Christ proclaims in the holy Scriptures the enjoyment of eternal blessedness. These prophets are his because they are not of another god but of the Father of Christ.”

“The Old Testament is full of predictions of Christ's coming. Paul did not call them "holy" by accident but, first of all, in order to teach that he recognized that the Old Testament was divinely inspired, and secondly, in order to exclude all other writings. For only the divinely inspired Scriptures are of any use. Indeed, Paul says that they are the image of the promise which was to come.”

“Since the preaching was reviled as an innovation, he shows that it is more ancient than paganism and was previously described by the prophets; even the word "gospel" is found in David, who says: "The Lord gives the word; the women who proclaim the good tidings are a great host" (Ps. 68:11), and in Isaiah: "How beautiful upon the mountains are the feet of him who brings good tidings, who publishes peace" (Isa. 52:7). The prophets not only spoke, but also wrote and depicted things through actions, for example: Abraham through Isaac, Moses through the serpent, the lifting up of hands, and the slaying of the lamb. For when God was about to prepare something great, He foretells it long beforehand. Therefore, when He says that many prophets desired to see what you see, and did not see it (Matt. 13:17), He expresses by this that they did not see His very flesh, and therefore did not see the signs being performed before their eyes.”

“The person of the writer described, now the task committed to him is commended, namely, the Gospel, which has already been commended from two viewpoints in the preceding verse. One of these concerns the usefulness it has due to its content, which is signified by its very name, Gospel, which implies that in it good things are announced. The other is based on the authority it has on the side of its author, which is set out when it says, of God (Rom 1:1). Now the Apostle pursues these two commendations further: first, on the part of the author; second, on the part of its content, at concerning his Son. From the first viewpoint the Gospel is commended in four ways: First, by its antiquity. This was required against the pagans, who belittled the Gospel as something suddenly appearing after all the preceding centuries. To counter this he says, which he had promised before, because, although it began to be preached at a certain point in time, it had been foretold previously in a divine way: before they came to pass, I announced them to you (Isa 48:5). Second, from its reliability, which is indicated when he says, he had promised, because the promise was made beforehand by one who does not lie: we bring you the good news that what God promised to the fathers, this he has fulfilled (Acts 13:32). Third, from the dignity of its ministers or witnesses, when he says, through his prophets, to whom had been revealed the things fulfilled concerning the incarnate Word: the Lord will not make a word, namely, make it be incarnate, without revealing his secret to his servants the prophets (Amos 3:7); to him all the prophets bear witness (Acts 10:43). It is significant that he says, his prophets, for some prophets spoke by a human spirit: they speak visions of their own minds, not from the mouth of the Lord (Jer 23:16). Hence, he says to Titus: one of themselves spoke, a prophet of their own (Titus 1:12). There are even prophets of demons who are inspired by an unclean spirit, such as the prophets whom Elijah slew (1 Kgs 18:40). But those are called God's prophets who are inspired by the divine Spirit: I will pour out my Spirit on all flesh and your sons and daughters will prophesy (Joel 2:28). Fourth, from the way it was delivered, because these promises were not merely spoken but recorded in writing. Hence he says, in the Scriptures: write the vision; make it plain upon tablets (Hab 2:2). For it was the custom to record only important matters worthy of remembrance and of being handed down to later generations. Consequently, as Augustine says in City of God XVIII, the prophecies about Christ made by Isaiah and Hosea began to be written when Rome was being founded, under whose rule Christ would be born and his faith preached to the gentiles: you search the Scriptures because you think to have eternal life by them (John 5:39). He adds holy to distinguish these writings from those of the gentiles. They are called holy, first, because, as it is written: men moved by the Holy Spirit spoke from God (2 Pet 1:21); all Scripture is inspired by God (2 Tim 3:16). Second, because they contain holy things: give thanks to his holy name (Ps 97:12). Third, because they make holy: make them holy in the truth; your word is truth (John 17:17). Hence, it is said: we have as encouragement the holy books which are in our hands (1 Macc 12:9).”

“"Which he had promised." In order to prove that the hope of faith was fulfilled and completed in Christ, Paul says that Christ's gospel was already promised by God beforehand, so that on the basis of the promise Paul could teach that Christ was the perfect author of [eternal] life."Through his prophets." In order to show even more clearly that the coming of Christ was a saving event, Paul also indicated the people through whom God gave his promise, so that it might be seen from them just how true and magnificent the promise is. For nobody uses great forerunners to announce some minor thing. "In the holy scriptures." Paul added this on top of his argument in order to give greater confidence to believers and show his approval of the law. The Scriptures are holy because they condemn sins and because in them is contained the covenant of the one God and the incarnation of the Son of God for the salvation of mankind, by the evidence of numerous signs.”