I don't think the concept of sin applies to angels and spirit creatures in general. Probably only applies to humans. Can an animal sin?? I don't think so.
I don't really believe that according to the bible human's have free will. Maybe the angels do, but definitely not humans. According to the bible god's exact's a price for our actions, especially if they are not according to his desires. So it's definitely not free.
And to make things worse he doesn't accept Visa, Mastercard, Diners or even American Express. Only currency he's interested in dealing with is death. Death of animals (e.g. sacrifices) & death of humans (e.g. flood and Jesus)
Just seems so petty and morbid.
DK