This is a quote from Ralph in Chapter 5. The deeper meaning has to do with civilization and the need to keep it alive.
When Ralph speaks this line, he is talking about the need to keep their immediate environment clean and the need to keep the fire going rather than trying to hunt pigs. In this context, the fire represents civilization and maturity and duty. Ralph wants the boys to keep these civilized virtues in mind rather than becoming lazy and dirty and hedonistic.
The deeper meaning of the quote, then, is that they ought to die rather than give up on being civilized. It is a statement of the value of maintaining civilization and civilized mores in the face of chaos.