Because of the fall of Man back in the garden in Ephesians 2 it says that we're spiritually dead in our trespasses which is why we need to be born again and until we are born again in spirit we are dead with the sin and death nature but once we are born again with the new nature we are no longer Sinners but Saints as it says clearly in the Epistles, we are a new creation in Christ the second Adam no longer in Union with the first Adam