Sin

"As it is written: “There is no one righteous, not even one. There is no one who understands, no one who seeks God. All have turned away, they have together become worthless; there is no one who does good, not even one. Their throats are open graves; their tongues practice deceit. The venom of vipers is on their lips. Their mouths are full of cursing and bitterness. Their feet are swift to shed blood; ruin and misery lie in their wake, and the way of peace they have not known. There is no fear of God before their eyes.” Romans 3:10-18

"For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord." Romans 6:23

"Then I saw a great white throne and the One seated on it. Earth and heaven fled from His presence, and no place was found for them. And I saw the dead, great and small, standing before the throne. And books were opened, and one of them was the Book of Life. And the dead were judged according to their deeds, as recorded in the books. The sea gave up its dead, and Death and Hades gave up their dead, and each one was judged according to his deeds. Then Death and Hades were thrown into the lake of fire. This is the second death—the lake of fire. And if anyone was found whose name was not written in the Book of Life, he was thrown into the lake of fire." Revelation 20:11-15

From the Westminster Standards (Larger Catechism 1647)

Q. 24. What is sin?
A. Sin is any want of conformity unto, or transgression of, any law of God, given as a rule to the reasonable creature.

Q. 25. Wherein consisteth the sinfulness of that estate whereinto man fell?
A. The sinfulness of that estate whereinto man fell, consisteth in the guilt of Adam’s first sin, the want of that righteousness wherein he was created, and the corruption of his nature, whereby he is utterly indisposed, disabled, and made opposite unto all that is spiritually good, and wholly inclined to all evil, and that continually; which is commonly called original sin, and from which do proceed all actual transgressions.

Q. 26. How is original sin conveyed from our first parents unto their posterity?
A. Original sin is conveyed from our first parents unto their posterity by natural generation, so as all that proceed from them in that way are conceived and born in sin.

Q. 27. What misery did the fall bring upon mankind?
A. The fall brought upon mankind the loss of communion with God, his displeasure and curse; so as we are by nature children of wrath, bond slaves to Satan, and justly liable to all punishments in this world, and that which is to come.

Q. 28. What are the punishments of sin in this world?
A. The punishments of sin in this world are either inward, as blindness of mind, a reprobate sense, strong delusions, hardness of heart, horror of conscience, and vile affections; or outward, as the curse of God upon the creatures for our sakes, and all other evils that befall us in our bodies, names, estates, relations, and employments; together with death itself.

Q. 29. What are the punishments of sin in the world to come?
A. The punishments of sin in the world to come, are everlasting separation from the comfortable presence of God, and most grievous torments in soul and body, without intermission, in hell-fire forever.