Overall, we would call this a poem that speaks softly and carries a big stick. It's quiet, with its subtle assonance and consonance, but there are also those heavy boots, that breath of gasoline, the airplane, that human ash. Those images make quite the clatter, mainly because they're so shocking.
Still, the poem is peaceful, don't you think? The sentences are short and simply worded, the images simple, if eerie. And it takes place at night, which gives the poem a feeling of hush. All that quiet has to have some effect, right? Right. That quiet accentuates whatever noises do come up in this piece.
Creaks in the attic become a dead brother walking around in heaven. That's quite a leap! It's that late-night hush when thoughts turn more potent than they would during the daytime. In lines 1 and 2, between the sounds of "Tonight my brother […] walking / […] over my head" we get the echo of those "o"-sounds in "boots […] / through bare rooms." Likewise, that needle piercing clean through in lines 18 and 19 is felt all the more sharply because there isn't a whole lot of noise around it. The words "needle" and "pierces" make sharp sounds, which are then accentuated by coming between duller sounds like "thread" and "hand."
It might remind you of that part in a ghost story, you know, just before the big finale, when the storyteller's voice grows low and quiet until BAM, the terrifying finish frightens you out of your wits. In this case, that terrifying finish is the haunting image of God as a furnace, with His hungry teeth.