The very first thing the speaker of "The Soldier" talks about is his own death. Throughout the first stanza, he talks about himself as "dust," a word that makes us immediately think of funerals, death, and corpses. Good times! Death almost seems inevitable, and this despite the fact that speaker says "If" in the very first line! We're used to thinking of death as scary, but the speaker imagines a life after death that seems, at the very least, peaceful and familiar.
By frequently referring to the soldier as dust, the speaker suggests that the soldiers who went off to war were already, in some sense, dead. Bummer.
Not so fast there, soldier. Imagining heaven as exactly the same as your favorite place on Earth is really not preparing yourself to die.