A bad man is a man with the higher side of his nature still undeveloped.

If he is selfish, the evil is not in his love of self--all love, even self-love, is good, is divine.

The evil is that he has such a poor, inadequate, misguided love of self and such a lack of love for others and for God.

He looks upon himself as only a superior sort of animal, and foolishly pampers his lower nature as he might pamper a pet dog--with worse results in his own case than in that of the dog.
In one of His letters 'Abdu'l-Baha says:-- As to thy remark, that 'Abdu'l-Baha hath said to some of the believers that evil never exists, nay rather, it is a nonexistent thing, this is but truth, inasmuch as the greatest evil is man's going astray and being veiled from truth.

Error is lack of guidance; darkness is absence of light; ignorance is lack of knowledge; falsehood is lack of truthfulness; blindness is lack of sight; and deafness is lack of hearing.