One should see the world, and see himself as a scale with an equal balance of good and evil. When he does one good deed the scale is tipped to the good - he and the world is saved. When he does one evil deed the scale is tipped to the bad - he and the world is destroyed.
MaimonidesThere is no difference between the pain of humans and the pain of other living beings, since the love and tenderness of the mother for the young are not produced by reasoning, but by feeling, and this faculty exists not only in humans but in most living beings.
Maimonides