The Gospel in the Old Testament: Romans 1:2
“1) Paul, a bond-servant of Christ Jesus, called as an apostle, set apart for the gospel of God, 2) which He promised beforehand through His prophets in the holy Scriptures,” Romans‬ ‭1:1-2‬
The Apostle Paul now makes a profound statement, the gospel of God can be found in the Old Testament. Indeed, he himself had only the Old Testament Scriptures to study and preach from for the New Testament was not yet given.
The gospel can be preached from the story of Abraham offering his son Issac on the altar as found in Genesis 22. At the last moment God interviewed and provided that ram as the substitute payment for Isaac.
The gospel can be preached from the Passover Meal in Exodus 12 and the blood of the lamb on the doorway of the house of every family that believed in God’s provision. The destroying angel passed over those homes, because a lamb had already died in place of the oldest son.
The gospel can be preached from Psalm 22 where nearly every word of Jesus was prophesied which He spoke from the cross. Indeed, the psalmist was so specific he even mentioned them casting lots for his garments.
The gospel can be preached from Isaiah 7:14 and Isaiah 9:6-7. From these verses we can conclude that a virgin was going to be with child and His identity was going to be Mighty God. It is a prophecy of the incarnation.
The gospel can be preached from Isaiah 53 and the suffering servant. This text is a picture of Jesus dying for the sins of humanity. It is so specific that little is left to human imagination.
This is merely scratching the surface of the many Old Testament references that point to the Messiah. Altogether there were over 300 Old Testament Prophecies about the Messiah. Paul was right, everything about the gospel was promised beforehand in the holy Scriptures.

Daily Bible Commentary By Terry Baxter: Cofounder of GoServ Global