Evil From the Heart - Westminster Confession 6.4-6

All people do bad things. Why? Some blame evil social influences, others explain sin as an evolutionary adaptation, the Bible teaches that Adam's seed are born with corrupt natures. Man is born opposite to good and inclined to evil. No part of human nature is untouched by sin; it comes from within us. American thinking on this point is quite confused, with many insisting that anything innate to us must be therefore good. Corruption remains in saved people. Even though their sin is pardoned and they have a new nature from God, yet lingering corruption produces sin in every believer. Every sin makes a person guilty before God and unfit for his presence in heaven, so every guilty sinner can expect God's wrath, the curse of the law, and finally death.