This is a reference to the title phrase of the book by Catherine Ryan Hyde
In the book the phrase is used as the opposite of payback
: when someone does a good dead for you, instead of paying them back, pay it forward by doing a good deed for someone else.
19:50 <Canaan> do u want something in return
19:51 <itchy> nah
19:51 <itchy> pay it forward
19:55 <Canaan> haha, will do
A phrase used to imply or otherwise act upon the action in which one would perform a deed of good service onto, for, or in the favor of another person or group of persons with the sound intentions that the only thing they do in return is to perform a deed of good service onto, for, or in the favor of another person or group of persons where in which they should maintain the same sound intentions of the individual or group who performed a good deed unto them. This method of kindness is infallible unless met with a person of great greed and/or immaturity.
Johnny helped the homeless man around the corner from his apartment with a fresh meal and a few dollars. Without any strings attached to this gesture of kindness, Johnny simply asked the man to pay it forward.