alphaparticle:
Romans 5:2
Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all men, because all sinned--
One man. Adam. And death came to all men.
That is, Adam must be the first man, otherwise we would have men before him who did not sin.
But Jesus is the only man who never sinned...
Do you agree that Adam was the first man?