Is defeating death.
Although the world has an idea of what this is, real success is what happens to you at the end of your time on this earth. It is not about career, or marriage, or family or money or fame.
True success is to please God, to stand, to fight the battle to the end, and like Christ/through Christ, defeat the enemy of death and live forever.
Where will you spend eternity?
Well done, thou good and faithful servant!