Are there any positive statements of the golden rule in extra-biblical literature? What is commonly called the golden rule is stated by Jesus in Matthew 7:12:


  In everything, treat others as you would want them to treat you, for
  this fulfills the law and the prophets. (NET)


Commentators often notice that the golden rule appears in extra-biblical literature, but often in negative form.

For example, Ben Witherington states:


  Jesus was by no means the first or only person to come up with a
  version of the Golden Rule. There is the famous saying of Rabbi
  Hillel, for example: “What is hateful to you, do not do to your
  neighbor: that is the whole Torah, while the rest is commentary on it;
  go and learn” (b. Sabb. 31a cf. Tob 4.15; 2 En. 61.1-2). It is worth
  pointing out that Jesus insists on a positive formulation of the
  maxim, where as other forms of it, both Jewish and Greco-Roman (cf.
  Isocrates Nic. 61; Herodotus 3.142), tend to be negative.


Are there any positive statements of this principle to be found in extra-biblical literature? (Excluding, of course, Christian literature or later literature influenced by Christianity)
Negative statements of the Golden Rule, often known as the Siver Rule, are, for some reason, far more numerous.  Wikipedia identifies several ancient versions of the (positive) Golden Rule:

The Stoic Philosophy of Seneca: Seneca the Younger (c. 4 BC–65 AD), a practitioner of Stoicism (c. 300 BC–200 AD) expressed the Golden Rule in his essay regarding the treatment of slaves: &quot;Treat your inferior as you would wish your superior to treat you.&quot;
Mahābhārata Shānti-Parva (Hindu): By making dharma (right conduct) your main focus, treat others as you treat yourself.
Sutrakritanga, 1.11.33 (Jain): A man should wander about treating all creatures as he himself would be treated.
Lord Mahavira, 24th Tirthankara (Jain): In happiness and suffering, in joy and grief, we should regard all creatures as we regard our own self.
Dao de Jing (Daoism): The sage has no interest of his own, but takes the interests of the people as his own. He is kind to the kind; he is also kind to the unkind: for Virtue is kind. He is faithful to the faithful; he is also faithful to the unfaithful: for Virtue is faithful.
T'ai Shang Kan Ying P'ien (Daoism): Regard your neighbor's gain as your own gain, and your neighbor's loss as your own loss.
Mozi (Mohism): If people regarded other people’s states in the same way that they regard their own, who then would incite their own state to attack that of another? For one would do for others as one would do for oneself. If people regarded other people’s cities in the same way that they regard their own, who then would incite their own city to attack that of another? For one would do for others as one would do for oneself. If people regarded other people’s families in the same way that they regard their own, who then would incite their own family to attack that of another? For one would do for others as one would do for oneself. And so if states and cities do not attack one another and families do not wreak havoc upon and steal from one another, would this be a harm to the world or a benefit? Of course one must say it is a benefit to the world.