The greatest gift we were given is free will, but we constantly misuse it.
The first sin was envy, and we killed our brother for what we envied, what we coveted. That was when we fell. When we fell, we brought down everything with us.
In the beginning there were no predators, no prey, just harmony. Yin and yang.
There was no time - time was all at once - no past, present, or future - and no death.
Now we have a broken world with poisonous plants, predators, earthquakes and flood.
Now we have time that steals everything from us.
Now we have death.
The world was a gift to us, a paradise and we broke it. To get back everything, we have to start by fixing ourselves. That's what sin is.