Pay it forward is an expression for describing the beneficiary of a good deed repaying it to others instead of to the original benefactor.
History The concept is Old... How Old you ask how about ancient Athens in 317 BC
Pay it Forward….The concept is old, but the phrase may have been coined by Menander around 317 BC
Dyskolos is an Ancient Greek comedy by Menander
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.
Again in a 1916 book, In the Garden of Delight
Interesting feature: On page 209, Hammond coins the phrase “pay it forward”, with the sentence: “You don’t pay love back; you pay it forward.”
"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 is an action made.
The concept was rediscovered 1784
The concept was rediscovered and described by Benjamin Franklin, in a letter to Benjamin Webb dated April 25, 1784:
Yes!!! Benjamin Franklin
I received yours of the 15th Instant, and the Memorial it inclosed. The account they give of your situation grieves me. I send you herewith a Bill for Ten Louis d’ors. I do not pretend to give such a Sum; I only lend it to you. When you shall return to your Country with a good Character, you cannot fail of getting into some Business, that will in time enable you to pay all your Debts. In that Case, 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. I am not rich enough to afford much in good works, and so am obliged to be cunning and make the most of a little. With best wishes for the success of your Memorial, and your future prosperity, I am, dear Sir, your most obedient servant,