What does the Bible say about our natural condition as humans?

In Mark 5, we see a vivid picture of mankind's natural condition through the man possessed by an unclean spirit. The scripture reveals that all have sinned and fall short of the glory of God, and are, by nature, like this man—unclean and unable to be bound by outward religious efforts. The prophet Isaiah declares that all our righteousness is like filthy rags, illustrating that our best works do not merit favor before God. We cannot tame our sinful nature on our own, for Scripture states that we are dead in trespasses and sins until God, in His rich mercy, speaks life into our cold hearts (Ephesians 2:1-5).