The First Man

“Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned” (Romans 5:12).
We read in 1 Corinthians 15:45 that Adam was “the first man.” God did not start by making a race of men.

The Bible makes it clear that only the descendants of Adam can be saved. Romans 5 teaches that we sin because Adam sinned. The death penalty, which Adam received as judgment for his sin of rebellion, has also been passed on to all his descendants.
Since Adam was the head of the human race, when he fell we who were in the loins of Adam fell also. Thus, we are all separated from God. The final consequence of sin would be separation from God in our sinful state forever. However, the good news is that there is a way for us to return to God.
Because a man brought sin and death into the world, the human race, who are all descendants of Adam, needed a sinless Man to pay the penalty for sin and the resulting judgment of death. However, the Bible teaches that “all have sinned” (Romans 3:23). What was the solution?
The Last Adam
God provided the solution—a way to deliver man from his wretched state. Paul explains in 1 Corinthians 15 that God provided another Adam. The Son of God became a man—a perfect Man—yet still our relation. He is called “the last Adam” (1 Corinthians 15:45) because he took the place of the first Adam. He became the new head and, because He was sinless, was able to pay the penalty for sin:
For since by [a] man came death, by [a] Man also came the resurrection of the dead. For as in Adam all die, even so in Christ all shall be made alive (1 Corinthians 15:21–22).
Christ suffered death (the penalty for sin) on the Cross, shedding His blood (“and without shedding of blood there is no remission,” Hebrews 9:22) so that those who put their trust in His work on the Cross can come in repentance of their sin of rebellion (in Adam) and be reconciled to God.
Thus, only descendants of the first man Adam can be saved.