The Stoic theorists agreed with Epicurus in inculcating the reciprocities of justice between all fellow-citizens; and they even went farther than he did, by extending the sphere of such duties beyond the limits of city, so as to comprehend all mankind.

But as to the reciprocities of individual friendship, Epicurus went beyond the Stoics, by the amount of self-sacrifice and devotion that he enjoined for the benefit of a friend.
There is also in the Stoical system a recognition of duties to God, and of morality as based on piety.

Not only are we all brethren, but also the 'children of one Father.' The extraordinary strain put upon human nature by the full Stoic _ideal_ of submerging self in the larger interests of being, led to various compromises.

The rigid following out of the ideal issued in one of the _paradoxes_, namely .-- That all the actions of the wise man are equally perfect, and that, short of the standard of perfection, all faults and vices are equal; that, for example, the man that killed a cock, without good reason, was as guilty as he that killed his father.
This has a meaning only when we draw a line between spirituality and morality, and treat the last as worthless in comparison of the first.
The later Stoics, however, in their exhortations to special branches of duty, gave a positive value to practical virtue, irrespective of the _ideal_.
The idea of Duty was of Stoical origin, fostered and developed by the Roman spirit and legislation.

The early Stoics had two different words,--one for the 'suitable' [Greek: kathaekon], or incomplete propriety, admitting of degrees, and below the point of rectitude, and another for the 'right' [Greek: katorthoma], or complete rectitude of action, which none could achieve except the wise man.