How do we know that believers still sin?

Although believers are justified and declared righteous through Christ, they still contend with a sinful nature. The Apostle Paul, in Romans 7:14, acknowledges this struggle by stating, 'For we know that the law is spiritual, but I am carnal, sold under sin.' Even as redeemed individuals, the reality of sin remains present in their lives, indicating that while they are made new, their old nature has not yet been eradicated.

1 John 1:8 highlights this truth when it states, 'If we say that we have no sin, we deceive ourselves, and the truth is not in us.' This acknowledgment is critical for believers; it points them towards dependence on Christ for forgiveness and cleansing, reminding them of His ongoing advocacy for them as they navigate their sinful inclinations while empowered by grace.