Why do religious people want to live?

This question has been lingering in my mind for some time. There are so many different religions, each describing an afterlife appropriate for the actions done in life for every person who has lived. There are many people who follow these teachings to the best of their abilities and believe that because of this they will go to a good place when they die. Yet despite the strong faith they have most of them would want to live as long as they can and fight with all their strength to avoid death and being murdered. Why is this so? Why do people who believe their existence will never be stopped view death as the ultimate end? Why do they fight to survive if they have earned an afterlife they claim to be much better than life is? I'm not encouraging suicide or murder as those are against the rules of most religions, but why strive to live if you are promised and have earned something better?