Why is faith in Christ crucial for overcoming sin?

The struggle against sin is an intrinsic part of the Christian life because of our fallen nature. Scripture explicitly states that all have sinned and fall short of the glory of God (Romans 3:23). However, through faith in Christ, believers find that their sin has already been dealt with at the cross. Hebrews 9:26 explains that Christ appeared to put away sin by the sacrifice of Himself. Only by believing in what Christ has accomplished can we truly overcome sin, knowing that He has already won the victory for us. It is His obedience, not ours, that is the basis of our hope and salvation.