came down like a wolf on the fold- sympathy is created as animal imagery is used.
the sheen of their spears was like stars on the sea- sibilance, hissing 's' sound, evil.
like leaves of the forest when Autumn hath blown.- biblical language is used, contrasts with other parts of the verse.
The Angel of Death spread his wings on the blast, and he breathed on the face of the foe as he passed.- biblical the angel can take an army it is much stronger. Anaphora is also used when repetition of the word 'and'.
the widows of Ashur are loud in their wail- the effects of death are ongoing, the wives of soldiers mourn the death.
And the might of the gentile... hath melted like snow in the glance of the lord.- all God has to do is glance this is important, this is what the poem finishes on. God is shown to have all the power.