As the following extracts show, all major religions agree on one basic aspect -- the need to treat others as we treat ourselves.  The basic Christian message (whether lived or not) is to love.  What is not always as obvious is the implication to love ourselves as we would love others.  As someone remarked 'If we talked to our friends the way talk to ourselves, then no one would stick around'.
 

Christian
All things whatsoever you would that men should do to you, do you even so to them: for this is the law and the prophets.
             Matthew 7. 12

Buddhist
Hurt not others with that which pains yourself.
             Udanavarga 5. 18

Jewish
What is hurtful to yourself do not do to your fellow man. That is the whole of the Torah and the remainder is but commentary. Go learn it.
            Talmud

Hindu
This is the sum of duty: do naught to others which if done to thee, would cause thee pain.
             Mahabarata 5. 1517

Islam
No one of you is a believer until he loves for his brother what he loves for himself.
            Traditions

Tao
Regard your neighbour's gain as your own gain: regard your neighbour's loss as your own loss.
            Tai Shan Kan Ying P'ien

Parsee
That nature only is good when it shall not do unto another whatsoever is not good for its own self.
             Dadistan-i-dinik 94,5

Confucian
Is there any one maxim which ought to be acted upon throughout one's life? Surely the maxim of loving kindness is such. Do not unto others what you would not that they should do unto you.
             Analects 15,23

Jain
In happiness and suffering, in joy and in grief, we should regard all creatures as we regard our own self, and should therefore refrain from inflicting upon others such injury as would appear undesirable to us if inflicted upon ourselves.
            Yogashastra 2,20

Sikh
As thou hast deemed thyself so deem others, then shalt thou become a partner in heaven.
             Kabir