the Old Testament actually tells us properly that our original sin is to eat (digest) the knowledge of 'good' & 'evil'
from our ideas of 'good' come our ideas of 'evil' & visa versa
from love comes hate & from hate comes love
for example, if you love Jehovah, you hate all other religions
pretty simple
Buddha explained the reality of original sin below:
On experiencing a phenomenon, he is passionate for it if it is pleasing; he is
angry with it if it is displeasing. He lives with attention to body unestablished, with a limited mind,
and he does not understand realistically the deliverance of mind and deliverance by wisdom wherein
those evil unwholesome states cease without remainder. Engaged as he is in favouring and opposing,
whatever feeling he feels - whether pleasant or painful or neither-pleasant-nor-painful - he delights in
that feeling, welcomes it, and remains holding on to it. As he does so, delight arises in him. Now
delight in feelings is clinging. Becoming is conditioned by his clinging; becoming conditions birth;
birth conditions ageing-&-death; sorrow, lamentation, pain, grief and despair come to be. Thus is the