What does the Bible say about salvation and human sinfulness?

Scripture clearly acknowledges the profound human depravity that necessitates divine intervention for salvation. Isaiah states, 'For we are all as an unclean thing, and all our righteousnesses are as filthy rags' (Isaiah 64:6). This indicates that human efforts at righteousness are ineffectual before God, as they stem from a nature marred by sin. Without acknowledging our sinful state, we cannot truly understand the grace offered through Christ. Salvation is solely the work of God, as we are completely incapable of saving ourselves because of our sinful nature.