The Cycle of Selfless Actions

"That selfless, thankless action you're taking will surely come back to you someday. People come to understand each other by repeating cycles of want and fulfillment. I believe events proceed with this as a premise. Nothing is useless, and nothing is meaningless. The quality of things is not determined by your judgment at that moment in time. The return on your 'selfless, thankless action' may be far in the future. But it will definitely return to you in some form."