4. From this original corruption, whereby we are utterly indisposed, disabled, and made opposite to all good, and wholly inclined to all evil, do proceed all actual transgressions.
5. This corruption of nature, during this life, doth remain in those that are regenerated; and although it be, through Christ, pardoned, and mortified; yet both itself, and all the motions thereof, are truly and properly sin.
6. Every sin, both original and actual, being a transgression of the righteous law of God, and contrary thereunto, doth, in its own nature, bring guilt upon the sinner, whereby he is bound over to the wrath of God, and curse of the law, and so made subject to death, with all miseries spiritual, temporal, and eternal.
WLC Q&A 24-29
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.
WSC Q&A 17-19
Q. 17. Into what estate did the fall bring mankind?
A. The fall brought mankind into an estate of sin and misery.
Q. 18. Wherein consists the sinfulness of that estate whereinto man fell?
A. The sinfulness of that estate whereinto man fell consists in the guilt of Adam’s first sin, the want of original righteousness, and the corruption of his whole nature, which is commonly called original sin; together with all actual transgressions which proceed from it.
Q. 19. What is the misery of that estate whereinto man fell?
A. All mankind by their fall lost communion with God, are under his wrath and curse, and so made liable to all miseries in this life, to death itself, and to the pains of hell forever.
Heidelberg Catechism Q&A 5-11
5. CAN YOU KEEP ALL THIS PERFECTLY?
No, for I am prone by nature to hate God and my neighbor.
6. DID GOD CREATE MAN THUS, WICKED AND PERVERSE?
No, but God created man good and after His own image, that is, in righteousness and true holiness, that he might rightly know God his Creator,heartily love Him, and live with Him in eternal blessedness, to praise and glorify Him.
7. FROM WHERE, THEN, DOES THIS DEPRAVED NATURE OF MAN COME?
From the fall and disobedience of our first parents, Adam and Eve, in Paradise,whereby our nature became so corrupt that we are all conceived and born in sin.
8. BUT ARE WE SO DEPRAVED THAT WE ARE COMPLETELY INCAPABLE OF ANY GOOD AND PRONE TO ALL EVIL?
Yes, unless we are born again by the Spirit of God.
9. DOES NOT GOD, THEN, DO INJUSTICE TO MAN BY REQUIRING OF HIM IN HIS LAW THAT WHICH HE CANNOT PERFORM?
No, for God so made man that he could perform it; but man, through the instigation of the devil, by willful disobedience deprived himself and all his descendants of this power.
10. WILL GOD ALLOW SUCH DISOBEDIENCE AND APOSTASY TO GO UNPUNISHED?
Certainly not, but He is terribly displeased with our inborn as well as our actual sins, and will punish them in just judgment in time and eternity, as He has declared: “Cursed is everyone that continues not in all things which are written in the book of the law to do them.”
11. BUT IS NOT GOD ALSO MERCIFUL?
God is indeed merciful, but He is likewise just; His justice therefore requires that sin which is committed against the most high majesty of God, be punished with extreme, that is, with everlasting punishment both of body and soul.
ARTICLE 15 – ORIGINAL SIN
We believe that by the disobedience of Adam original sin has spread throughout the whole human race.1 It is a corruption of the entire nature of man2 and a hereditary evil which infects even infants in their mother’s womb.3 As a root it produces in man all sorts of sin. It is, therefore, so vile and abominable in the sight of God that it is sufficient to condemn the human race.4 It is not abolished nor eradicated even by baptism, for sin continually streams forth like water welling up from this woeful source.5 Yet, in spite of all this, original sin is not imputed to the children of God to their condemnation but by His grace and mercy is forgiven them.6 This does not mean that the believers may sleep peacefully in their sin, but that the awareness of this corruption may make them often groan as they eagerly wait to be delivered from this body of death.
In this regard we reject the error of the Pelagians, who say that this sin is only a matter of imitation.