Cremation and Burial

People knew perfectly well that people would die in fires, that their bodies would be reduced to ashes. Early christians don't seem to bother about any of those as that's what's going to happen. A c s lewis makes the point in his book miracles that resurrection doesn't mean that we get the exact same bits and pieces back again. God an god can do that if he wants to, but actually, we share stuff around an our bodies are in a constant state of flux.