Westminster Shorter Catechism

Q18

Wherein consists the sinfulness of that estate whereinto man fell?

The sinfulness of that estate whereinto man fell, consists in the guilt of Adam’s first sin43, the want of original righteousness44, and the corruption of his whole nature45, which is commonly called original sin; together with all actual transgressions which proceed from it46.
Doctrine
Ch. VI Of the Fall of Man, of Sin, and of the Punishment thereof

Scripture Proofs

43
Romans 5:12Romans 5:19
44
Romans 3:10Colossians 3:10Ephesians 4:24
45
Psalm 51:5John 3:6Romans 3:18Romans 8:7-8Ephesians 2:3
46
Genesis 6:5Psalm 53:1-3Matthew 15:19Romans 3:10-18Romans 3:23