Move him into the sun—
Gently its touch awoke him once,
At home, whispering of fields unsown.
Always it woke him, even in France,
Until this morning and this snow.
If anything might rouse him now
The kind old sun will know.
Think how it wakes the seeds—
Woke, once, the clays of a cold star.
Are limbs so dear-achieved, are sides
Full-nerved,—still warm,—too hard to stir?
Was it for this the clay grew tall?
—O what made fatuous sunbeams toil
To break earth's sleep at all?
The narrator asks if this young man, the result of ages of evolution — ‘dear-achieved’ and ‘full-nerved’ — can be revived. 
 
 On a literal level the soldier is ‘still warm’ so hope has not died yet.  ‘Too hard to stir’ may refer to rigor mortis, the stiffness of a recently-deceased corpse. On a symbolic level, the soldier represents the absolute nature of death. 
 These two lines, like the two that precede them, are halting and choppy, to reflect the grief and bafflement of the narrator and those who grieve for a fallen comrade. They perhaps even imitate gulping, sobbing breaths.