Pay it forward is an expression for describing the beneficiary of a good deed repaying it to others instead of to the original benefactor.
The concept is old, but the phrase may have been coined by Lily Hardy Hammond in her 1916 book In the Garden of Delight.
"Pay it forward" is implemented in contract law of loans in the concept of third party beneficiaries. Specifically, the creditor offers the debtor the option of paying the debt forward by lending it to a third person instead of paying it back to the original creditor. This contract may include the provision that the debtor may repay the debt in kind, lending the same amount to a similarly disadvantaged party once they have the means, and under the same conditions. Debt and payments can be monetary or by good deeds. A related type of transaction, which starts with a gift instead of a loan, is alternative giving.
Pay it forward was used as a key plot element in the denouement of a New Comedy play by Menander, Dyskolos (a title which can be translated as "The Grouch"). Dyskolos was a prizewinning play in ancient Athens in 317 BC; however, the text of the play was lost and it was only recovered and republished in 1957.
I do not pretend to give such a deed; I only lend it to you. When you [...] meet with another honest Man in similar Distress, you must pay me by lending this Sum to him; enjoining him to discharge the Debt by a like operation, when he shall be able, and shall meet with another opportunity. I hope it may thus go thro' many hands, before it meets with a Knave that will stop its Progress. This is a trick of mine for doing a deal of good with a little money.
Ralph Waldo Emerson, in his 1841 essay "Compensation", wrote: "In the order of nature we cannot render benefits to those from whom we receive them, or only seldom. But the benefit we receive must be rendered again, line for line, deed for deed, cent for cent, to somebody."
In 1916, Lily Hardy Hammond wrote, "You don't pay love back; you pay it forward."
Woody Hayes (February 14, 1913 – March 12, 1987) was a college football coach who is best remembered for winning five national titles and 13 Big Ten championships in 28 years at The Ohio State University. He misquoted Emerson as having said "You can pay back only seldom. You can always pay forward, and you must pay line for line, deed for deed, and cent for cent." He also shortened the (mis)quotation into "You can never pay back; but you can always pay forward" and variants.
The banker reached into the folds of his gown, pulled out a single credit note. "But eat first—a full belly steadies the judgment. Do me the honor of accepting this as our welcome to the newcomer."
His pride said no; his stomach said YES! Don took it and said, "Uh, thanks! That's awfully kind of you. I'll pay it back, first chance."
"Instead, pay it forward to some other brother who needs it."
Heinlein both preached and practiced this philosophy. Today, the Heinlein Society, a humanitarian organization founded in his name, practices it in the form of various programs such as blood drives, free educational CDs for teachers, and US$500 scholarships.
Author Spider Robinson made repeated reference to the doctrine, attributing it to his spiritual mentor Heinlein.[failed verification]
Heinlein was a mentor to Ray Bradbury, giving him help and quite possibly passing on the concept, made famous by the publication of a letter from him to Heinlein thanking him. In Bradbury's novel Dandelion Wine, published in 1957, when the main character Douglas Spaulding is reflecting on his life being saved by Mr. Jonas, the Junkman:
How do I thank Mr. Jonas, he wondered, for what he's done? How do I thank him, how pay him back? No way, no way at all. You just can't pay. What then? What? Pass it on somehow, he thought, pass it on to someone else. Keep the chain moving. Look around, find someone, and pass it on. That was the only way....
Bradbury has also advised that writers he has helped thank him by helping other writers.