Why did God allow sin into the world at all?

Genesis 3:1–15

¹Now the serpent was more subtil than any beast of the field which the LORD God had made. And he said unto the woman, Yea, hath God said, Ye shall not eat of every tree of the garden? ²And the woman said unto the serpent, We may eat of the fruit of the trees of the garden: ³But of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die. ⁴And the serpent said unto the woman, Ye shall not surely die: ⁵For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil. ⁶And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat. ⁷And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons. ⁸And they heard the voice of the LORD God walking in the garden in the cool of the day: and Adam and his wife hid themselves from the presence of the LORD God amongst the trees of the garden. ⁹And the LORD God called unto Adam, and said unto him, Where art thou? ¹⁰And he said, I heard thy voice in the garden, and I was afraid, because I was naked; and I hid myself. ¹¹And he said, Who told thee that thou wast naked? Hast thou eaten of the tree, whereof I commanded thee that thou shouldest not eat? ¹²And the man said, The woman whom thou gavest to be with me, she gave me of the tree, and I did eat. ¹³And the LORD God said unto the woman, What is this that thou hast done? And the woman said, The serpent beguiled me, and I did eat. ¹⁴And the LORD God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life: ¹⁵And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.

Romans 5:12–21

¹²Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned: ¹³(For until the law sin was in the world: but sin is not imputed when there is no law. ¹⁴Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam’s transgression, who is the figure of him that was to come. ¹⁵But not as the offence, so also is the free gift. For if through the offence of one many be dead, much more the grace of God, and the gift by grace, which is by one man, Jesus Christ, hath abounded unto many. ¹⁶And not as it was by one that sinned, so is the gift: for the judgment was by one to condemnation, but the free gift is of many offences unto justification. ¹⁷For if by one man’s offence death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.) ¹⁸Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life. ¹⁹For as by one man’s disobedience many were made sinners, so by the obedience of one shall many be made righteous. ²⁰Moreover the law entered, that the offence might abound. But where sin abounded, grace did much more abound: ²¹That as sin hath reigned unto death, even so might grace reign through righteousness unto eternal life by Jesus Christ our Lord.

Romans 8:18–23

¹⁸For I reckon that the sufferings of this present time are not worthy to be compared with the glory which shall be revealed in us. ¹⁹For the earnest expectation of the creature waiteth for the manifestation of the sons of God. ²⁰For the creature was made subject to vanity, not willingly, but by reason of him who hath subjected the same in hope, ²¹Because the creature itself also shall be delivered from the bondage of corruption into the glorious liberty of the children of God. ²²For we know that the whole creation groaneth and travaileth in pain together until now. ²³And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, the redemption of our body.

Job 38:1–11

¹Then the LORD answered Job out of the whirlwind, and said, ²Who is this that darkeneth counsel by words without knowledge? ³Gird up now thy loins like a man; for I will demand of thee, and answer thou me. ⁴Where wast thou when I laid the foundations of the earth? declare, if thou hast understanding. ⁵Who hath laid the measures thereof, if thou knowest? or who hath stretched the line upon it? ⁶Whereupon are the foundations thereof fastened? or who laid the corner stone thereof; ⁷When the morning stars sang together, and all the sons of God shouted for joy? ⁸Or who shut up the sea with doors, when it brake forth, as if it had issued out of the womb? ⁹When I made the cloud the garment thereof, and thick darkness a swaddlingband for it, ¹⁰And brake up for it my decreed place, and set bars and doors, ¹¹And said, Hitherto shalt thou come, but no further: and here shall thy proud waves be stayed?