1. Our first parents, being seduced by the subtlety and temptation of Satan, sinned, in eating the forbidden fruit. This their sin, God was pleased, according to his wise and holy counsel, to permit, having purposed to order it to his own glory.
2. By this sin they fell from their original righteousness and communion with God, and so became dead in sin, and wholly defiled in all the parts and faculties of soul and body.
3. They being the root of all mankind, the guilt of this sin was imputed; and the same death in sin, and corrupted nature, conveyed to all their posterity descending from them by ordinary generation.
WLC Q&A 19-24
Q. 19. What is God’s providence towards the angels?
A. God by his providence permitted some of the angels, willfully and irrecoverably, to fall into sin and damnation, limiting and ordering that, and all their sins, to his own glory; and established the rest in holiness and happiness; employing them all, at his pleasure, in the administrations of his power, mercy, and justice.
Q. 20. What was the providence of God toward man in the estate in which he was created?
A. The providence of God toward man in the estate in which he was created, was the placing him in paradise, appointing him to dress it, giving him liberty to eat of the fruit of the earth; putting the creatures under his dominion, and ordaining marriage for his help; affording him communion with himself; instituting the Sabbath; entering into a covenant of life with him, upon condition of personal, perfect, and perpetual obedience, of which the tree of life was a pledge; and forbidding to eat of the tree of the knowledge of good and evil, upon the pain of death.
Q. 21. Did man continue in that estate wherein God at first created him?
A. Our first parents being left to the freedom of their own will, through the temptation of Satan, transgressed the commandment of God in eating the forbidden fruit; and thereby fell from the estate of innocency wherein they were created.
Q. 22. Did all mankind fall in that first transgression?
A. The covenant being made with Adam as a public person, not for himself only, but for his posterity, all mankind descending from him by ordinary generation, sinned in him, and fell with him in that first transgression.
Q. 23. Into what estate did the fall bring mankind?
A. The fall brought mankind into an estate of sin and misery.
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. 12. What special act of providence did God exercise toward man in the estate wherein he was created?
A. When God had created man, he entered into a covenant of life with him, upon condition of perfect obedience; forbidding him to eat of the tree of the knowledge of good and evil, upon the pain of death.
Q. 13. Did our first parents continue in the estate wherein they were created?
A. Our first parents, being left to the freedom of their own will, fell from the estate wherein they were created, by sinning against God.
Q. 14. What is sin?
A. Sin is any want of conformity unto, or transgression of, the law of God.
Q. 15. What was the sin whereby our first parents fell from the estate wherein they were created?
A. The sin whereby our first parents fell from the estate wherein they were created was their eating the forbidden fruit.
Q. 16. Did all mankind fall in Adam’s first transgression?
A. The covenant being made with Adam, not only for himself, but for his posterity; all mankind, descending from him by ordinary generation, sinned in him, and fell with him, in his first transgression.
The Belgic Confession Article 14-15
ARTICLE 14 – THE CREATION AND FALL OF MAN AND HIS INCAPABILITY OF DOING WHAT IS TRULY GOOD
We believe that God created man of dust from the ground1 and He made and formed him after His own image and likeness, good, righteous, and holy.2 His will could conform to the will of God inevery respect. But, when man was in this high position, he did not appreciate it nor did he value his excellency. He gave ear to the words of the devil and wilfully subjected himself to sin and consequently to death and the curse.3 For he transgressed the commandment of life which he had received; by his sin he broke away from God, who was his true life; he corrupted his whole nature. By all this he made himself liable to physical and spiritual death.4
Since man became wicked and perverse, corrupt in all his ways, he has lost all his excellent gifts which he had once received from God.5 He has nothing left but some small traces, which are sufficient to make man inexcusable.6 For whatever light is in us has changed into darkness,7 as Scripture teaches us, The light shines in the darkness, and the darkness has not overcome it (John 1:5); where the apostle John calls mankind darkness.
Therefore we reject all teaching contrary to this concerning the free will of man, since man is but a slave to sin (John 8:34) and no one can receive anything except what is given him from heaven (John 3:27). For who dares to boast that he of himself can do any good, when Christ says: No one can come to Me unless the Father who sent Me draws him (John 6:44)? Who will glory in his own will, when he understands that the mind that is set on the flesh is hostile to God (Rom 8:7)? Who can speak of his knowledge, since the unspiritual man does not receive the gifts of the Spirit of God (1 Cor 2:14)? In short, who dares to claim anything, when he realizes that we are not competent of ourselves to claim anything as coming from us, but that our competence is from God (2 Cor 3:5)? Therefore what the apostle says must justly remain sure and firm: God is at work in you both to will and to work for His good pleasure (Phil 2:13). For there is no understanding nor will conformable to the understanding and will of God unless Christ has brought it about; as He teaches us: Apart from Me you can do nothing (John 15:5).
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.
Heidelberg Catechism Q&A 6-8
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.