The English word “gospel” is an approximation of the Greek word εὐαγγέλιον (euangelion) which means “good news” (Friberg). While it is presently in vogue to refer to the whole Bible, or at least salvation history, as “the gospel,” this term is probably best reserved for the specific work of God in Christ—his incarnation, his words, his works, his suffering and death, his resurrection, his ascension to the right hand of the Father, and his eternal reign as King and High Priest—all of which he did in glad submission to his Father, for the glory of his Father, and for the salvation of all who believe in him (John 3:16; 5:19; 8:28; 15:11; 17:1-26; Phil 2:5-11; Heb 1:1-4).
Accordingly, the term “gospel” first emerges in the Gospels and not before (Matt 4:23; Mark 1:1; Luke 9:6). Surely, when the Apostles and early disciples preached the gospel, they were in part drawing on the OT to do so (Acts 8:25, 40; 14:7, 21; 15:7; 16:10; 20:23-24). That is, their preaching of the OT was not a mere exposition of the text but exposition with special reference to Christ (e.g., Acts 28:23). This Apostolic practice implies that the gospel is clearly and broadly prophesied, promised, and foreshadowed in the OT, but it does not imply that the OT itself is the gospel. Rather, it is better to envision the story-arc of the OT as preparation for the gospel, and to reserve the term itself for the time of fulfillment, for what Paul calls “the gospel of his Son” (Rom 1:9, 16), “the gospel of Christ” (1 Cor 9:12), and “the gospel of your salvation” (Eph 1:13; emphasis mine).
Paul does write in Gal 3:8-9, “And the Scripture [i.e., the OT], foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, ‘In you shall all the nations be blessed.’ So then, those who are of faith are blessed along with Abraham, the man of faith” (emphasis mine). However, this statement refers to the gospel foreseen and not to the gospel revealed, and it does not imply that the term “gospel” properly describes every word or pericope of the OT. Indeed, even for those portions of the OT that explicitly reference Christ, the gospel is not that Jesus will come but that he has come. It is not that the Christ will be Jesus, but that the Christ is Jesus, and that by believing in him we may have eternal life (John 20:31).
I joyfully affirm that the entire OT is a prelude to the gospel proper and that the gospel is being foreshadowed and even preached from the very first words thereof, namely, “in the beginning” and “let there be light” (John 1:1-5; 2 Cor 4:5-6; Col 1:15-17; Heb 1:1-4; 1 John 1:1-5). I delight in the truth that Christ is both the inspiration and the fulfillment of every word spoken in the law, the prophets, and the writings (1 Pet 1:10-12). But I agree with John Calvin when he argues that we should reserve the term “gospel” for the specific work of God in Christ.
Some consider the word Gospel as extending to all the gracious promises of God which are found scattered even in the Law and the Prophets. Nor can it be denied that, whenever God declares that he will be reconciled to men, and forgives their sins, he at the same time exhibits Christ, whose peculiar office it is, wherever he shines, to spread abroad the rays of joy. I acknowledge, therefore, that the Fathers were partakers of the same Gospel with ourselves, so far as relates to the faith of a gratuitous salvation. But as it is the ordinary declaration made by the Holy Spirit in the Scriptures, that the Gospel was first proclaimed when Christ came, let us also adhere to this mode of expression; and let us keep by that definition of the Gospel which I have given, that it is a solemn publication of the grace revealed in Christ (Calvin, 11).
To embrace this point of view neither diminishes the importance of the OT nor denies the ubiquitous presence of the gospel-seeds that are there. To the contrary, this point of view helps us to see how the Bible comes to a crescendo and how the gospel brings all of its parts into sharp focus. As Carson notes, “Rightly done, [teaching and] preaching from the Gospels enables a congregation to put its Bible together, and then to find the Bible’s deepest and most transforming application emerging from this vision…Preaching from the Gospels is above all an exercise in the exposition and application of Christology” (Carson, 102), and such an exercise demands that the object of our exposition be the entire text of Scripture.
Calvin, John. 1553. Commentary on the Gospel According to John: Volume I, trans. William Pringle, 1847. Grand Rapids: Christian Classics Ethereal Library.
Carson, D. A. 1991. The Gospel According to John. The Pillar New Testament Commentary. Grand Rapids: Eerdmans.
Friberg, Timothy, Barbara Friberg, and Neva F. Miller. 2005. Analytical Lexicon of the Greek New Testament. Victoria, BC, Canada: Trafford.