Short Answer:  Sin entered the world when the first husband and wife came into spiritual agreement that eating the fruit of unrighteousness was acceptable.   What the Bible Says ·          This  is  now bone of my bones and flesh of my flesh ( Genesis 2:23 )       So when the woman saw that the tree  was  good for food, that it  was  pleasant to the eyes, and a tree desirable to make  one  wise, she took of its fruit and ate. She also gave some to her husband with her, and he ate. ( Genesis 3:6 )   Although Eve was the first to eat the fruit ( Genesis 3:6 ), we’re told that sin entered the world through one man ( Romans 5:12 ) - Adam. The argument that Adam bears responsibility because he was created first is valid, but alone this explanation misses a deeper spiritual truth. When God brought Eve to Adam, Adam said, “This  is  now bone of my bones and fles...