How do we know our sinful nature is real?

The concept of our sinful nature is rooted in the doctrine of original sin, which teaches that all humanity fell into sin through Adam's disobedience (Genesis 3). Romans 5:12 states that '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.' This indicates that every person inherits a corruptible nature from Adam, characterized by a mind that embraces sin. Furthermore, the consistent struggle against sin in a believer’s life serves as evidence of this sin nature. Paul articulates this struggle in Romans 7:24, expressing, 'O wretched man that I am! who shall deliver me from the body of this death?' This conflict of the spirit against the flesh demonstrates the reality of our sinful nature and the need for divine grace.