The very first prophet mentioned in the Bible was Abel the son of our first parents, Adam and Eve (Luke 11:50, 51). And according to the same writer, Luke, all the prophets foretold of the future suffering of the Messiah [Christ] (Acts 3:18). In a conversation with King Agrippa, the apostle Paul said that he testified of the same things that the prophets foretold. The prophets said that the Christ would suffer and be the first to rise from the dead (Acts 26:23).
It seems as though the Old Testament saints knew more than we give them credit. The grace of our God was there communicating the truth of restoration and salvation from the very beginning. “For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish, but have everlasting life” (John 3:16). The Old Testament saints look forward by faith to the coming of the Christ, understanding that He would die for sin and rise again. New Testament saints look backward to the death and resurrection of Christ by faith. Salvation is the same for all people. It’s always been by God’s grace through faith in the substitutionary sacrifice and resurrection of Jesus Christ.
Assurance of Heaven 