Paul says in Romans 10:9 that, “If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.” But how then could Old Testament saints be saved since they did not know about the resurrection of Christ? If the proclamation of the gospel is a “mystery that was kept secret for long ages” (Rom 16:25), how could anyone be saved before the coming of the Messiah? Were people saved apart from belief in the good news about the Messiah? The answer is no. When Paul speaks of the gospel as a “mystery”, he does not mean that it was completely unknown in the Old Testament, but rather, it was revealed, but not fully understood until the coming of Christ. The Messiah comes in two stages: first as a suffering servant, and then as a conquering king. The Old Testament depicts the Messiah in both these ways, but the two-stage coming of Christ was not grasped until Jesus’ first coming as the one who fulfills the prophecy of Isaiah 53 and then revealed that he would come again a second time (Acts 1:11). In this sense, the gospel was a mystery, but the call to faith in the one true God and repentance has always been the same. We are saved looking back to the finished work of the cross and the empty tomb while Old Testament saints were saved believing in the promise of the Messiah who would deliver them from Satan and their enemies.
The first reference to the gospel in Scripture is Genesis 3:15 or the protoevangelium which says that God would use a descendant of Eve to defeat the serpent who deceived mankind and led them into sin. Those who were saved in the early days of creation were saved by believing in the promise of God and demonstrating their faith in God by approaching him with blood which foreshadowed the death of Christ. Adam and Eve were covered with the garments of slain animals, Abel approached God with sacrificial animals, and Noah offered sacrifices to God.
Abraham was justified by believing in God’s promise that through his descendant, God would bless all nations (Gen 15:6). Jesus reaffirms this truth when he says Abraham saw his day and was glad (John 8:56). Abraham is our father in the faith and we are called to imitate his faith and trust in God (Rom 4:16; Gal 3:7; Heb 11:17). Hebrews 11 demonstrates the continuity that we share with those who were believers in the Old Testament. We all worship and believe in the same God regardless of whether we lived before or after Christ.
Job, who I believe was a contemporary of Abraham, believed in Christ as demonstrated by his longing for one who could intercede between him and God (Job 9:33-35; 33:24). He prophesied concerning the resurrection of Christ (Job 19:25) and believed that God would resurrect him from the dead so he could see his redeemer (Job 19:26-27). James affirms the faith of Job as well (Jam 5:11).
The Messiah is prophesied in several places throughout the Old Testament. The great prophecy of Isaiah 53 presents the Messiah’s suffering role as clearly as someone who stood in front of the cross. Psalm 22 likewise describes a suffering servant whose suffering transcendes that which David went through. Daniel 9:24-27 gives us the exact time when the Messiah would be put to death to atone for sin. Jesus taught that all of Scripture points to him (Luke 24:25-27; John 5:39; 1 Pet 1:11). Other texts that at least allude to the Messiah include: Numbers 24:17; Psalm 2:11-12; 110:1-4; Isaiah 28:16; 48:16; Micah 5:2; and “the angel of the Lord” texts.
Salvation has always been by faith and not by works. It’s called the “eternal gospel” (Rev 14:6) for a reason. Isaiah 55 is beautiful presentation of the gospel which invites sinners to return to God “without money and without price.” Isaiah 45:22 expresses this truth as well when God says, “Turn to me and be saved, all the ends of the earth! For I am God, and there is no other.” The early Christian writing of 1 Clement declares that faith is the only means of salvation when it says, “but by that faith through which, from the beginning, Almighty God has justified all men.” The church father Clement of Alexandria affirmed this also when he says, “The same from the foundation of the world is each one who at different periods is saved, and will be saved by faith.” The longer edited version of Ignatius’ letter to the Philippians echoes the same truth:
“For there is one God of the Old and New Testament, ‘one Mediator between God and men,’ for the creation of both intelligent and sensitive beings, and in order to exercise a beneficial and suitable providence. There is also one Comforter, who displayed His power in Moses, and the prophets, and apostles. All the saints, therefore, were saved by Christ, hoping in Him, and waiting for Him; and they obtained through Him salvation, being holy ones, worthy of love and admiration, having testimony borne to them by Jesus Christ, in the Gospel of our common hope.”