What is past is gone forever. Something else can and will take place, but the past event itself can never return.
Every moment comes but once, and that is why life is ever new.
Something in us is continually welcoming what is about to come, and mourning what is about to go. And the transitory is always brief, no matter how long it lasts. It is the opposite of eternal. Natural science teaches us that nothing in the world can be lost. The whole system, however, exists only for an instant.