The word "England" or "English" occurs six times in this poem. That's a lot for a poem that is only 14 lines! In this poem England is like a mother to the soldier; she gave birth to him, nourished him, made him who he is. But England is also immortal. Even though, in death, the soldier must leave England, it's only for a little while. When he dies, the soldier will go to a heaven that's just like the England he left behind on Earth. Sweet deal!
Lines 2-3: The soldier wishes to be remembered for making a foreign piece of land "forever England." This idea of a permanent, immortal England will return again soon.
Line 5: The speaker compares himself to dust that "England bore." Dust here is a metaphor for the speaker's relationship to the natural world and for the fact that he may soon be a corpse. Of course, England can't really bear children so this is an example of personification, the attribution of human qualities to non-human things.
Line 7: The speaker refers to himself as a "body of England's, breathing English air." He's as English as the Queen!
Line 11: The speaker will re-experience in heaven "thoughts by England given." England can't really give anything, so this is another example of personification (the attribution of human qualities to non-human things). It's also another example of how the experience of England will live on for our speaker.
Line 14: When the soldier dies he will go to an "English heaven." Sweet. We bet they serve the best fish n' chips.