What does the Bible say about the significance of Adam in relation to sin?

According to Romans 5:12, by one man, sin entered the world, and death came as a consequence of that sin. Adam, as the federal head of humanity, represents all mankind in his disobedience. His actions brought about spiritual death for all who are descended from him. This doctrine aligns with the Reformed understanding of original sin, highlighting humanity's need for redemption through Christ. In Adam, all have sinned and consequently bear the effects of his transgression (1 Corinthians 15:22).