To say that life ends at death is far too simple a climax for the story that is our lives. There is more than biology at work inside us.
In the Hebrew scriptures, it's said that God himself wrote eternity on our hearts. Deep down, we sense it. Our lives are leading up to something. Our Choices, public and private, count, not only for this life, but in the one to come. Actions, in that sense, are forever.