How do we know that sin entered the world through Adam?

Romans 5:12 explicitly states that by one man, sin entered into the world, and death by sin. This verse highlights the theological understanding that Adam's disobedience had repercussions for all humanity, making him the head of the human race. This concept of original sin signifies that all are inextricably linked to Adam's fall, evidencing the total depravity and sinful nature inherited by all descendants. It illustrates the necessity of Christ, the last Adam, whose obedience and sacrifice provide redemption for sinners (1 Corinthians 15:45).