Who is credited with writing or saying The Golden Rule?

500BC - CONFUCIOUS. "never impose on others what you would not choose for yourself"

Jesus Christ said in Matt 7-12

...Do unto others as you would have them do unto you... The wording may vary depending upon the translation you chose, but that is the text from which the GR was taken.

That, like almost all, of the rules, standards and laws in the Western world come from Judeo-Christian writing and values.

This is broadly called "The ethics of reciprocity" and it's been around for a long time.

It's actually better expressed as a negative than a positive. As in "Do not do to others what you would not wish them to do to you"

It's very old idea, and no one is actually sure when this rule for ethical behavior first developed.

Some "Ethic of Reciprocity" passages from the religious texts of various religions and secular beliefs:

http://www.religioustolerance.org/reciproc.htm

The Golden Rule was derived from the social philosophy of Confucius.....

I believe that Jesus said "whatever you do to the least of my brethren, you do unto me."

Solomon

Matthew 7:12 NWT: "All things, therefore, that you want men to do to you, you also must likewise do to them; this, in fact, is what the Law and the Prophets mean."

Jesus speaking.

I believe that Jesus taught this, but the Bible doesn't call it the Golden Rule.

Jesus is most famous for saying it in his Sermon on the Mount. The principle dates way back before he said it.

I believe it goes back to ancient Greece but nobody knows the author.

(Jesus speaking)

Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.

(Matthew 7:12)

It is a common teaching in many religions. I don't know who was first.