Reciprocity refers to in-kind positive or negative responses of individuals towards the actions of other. It is applied in acoustics, laser physics and in community and organisation develoment for example merging police and fire services. It's also a universal principle that religions have also articulated.
As Hillel, the author of Shabbat 31a implies - follow these and the rest of religion is just commentary; interesting but not all that important. In my humble opinion anyway. Sorry I'm not taking the time to format it to be more readable. Feel free to add to it.
African Indigenous
Ubuntu
Your pain is my pain, My wealth is your wealth, Your salvation is my salvation. - It is through others that one attains selfhood.
Yoruba
One going to take a pointed stick to pinch a baby bird should first try it on himself to feel how it hurts."
Buddhism
Hurt not others in ways that you yourself would find hurtful. -Udana-Varga 5:18
.a state that is not pleasing or delightful to me, how could I inflict that upon another?" -Samyutta NIkaya v. 353
Christianity
(Pauline scriptures)
So in everything, do to others what you would have them do to you, for this sums up the Law and the Prophets. -Matthew 7:12
"And as ye would that men should do to you, do ye also to them likewise." -Luke 6:31, King James Version.
(non-Pauline)
"...and don't do what you hate...", Gospel of Thomas 6
Confucianism
Surely it is the maxim of loving-kindness: Do not unto others what you would not have done unto you. -Analects 15:23
Tse-kung asked, 'Is there one word that can serve as a principle of conduct for life?' Confucius replied, 'It is the word 'shu' -- reciprocity. Do not impose on others what you yourself do not desire.” -Doctrine of the Mean 13.3
Try your best to treat others as you would wish to be treated yourself, and you will find that this is the shortest way to benevolence. -Mencius VII.A.4
Hinduism
This is the sum of duty: Do naught unto others which would cause you pain if done to you. -Mahabharata 5:1517
Islam
None of you [truly] believes until he wishes for his brother what he wishes for himself. Sunna- Number 13 of Imam "Al-Nawawi's Forty Hadiths."
Judaism
What is hateful to you, do not to your fellow man. That is the entire Law; all the rest is commentary. -Talmud, Shabbat 31a
"And what you hate, do not do to any one." -Tobit 4:15
Taoism
Regard your neighbor’s gain as your own gain and your neighbor’s loss as your own loss. -T’ai Shang Kan Ying P’ien
Zoroastrianism
That nature alone is good which refrains from doing unto another whatsoever is not good for itself -Dadistan-i-dinik 94:5
Whatever is disagreeable to yourself do not do unto others. Shayast-na-Shayast 13:29 Source
