Some are in bed-sheets, some are in blouses,
Some are in smocks: but truly there they are.
The speaker notes that the angels, though supernatural by definition, appear in the daily laundry drawn (presumably) from his own life and mind. And he insists to himself that the angels are no figment; that they are real, at least in this vision. The question of the angels' reality, of what it might mean for a dream vision to be "real," animates the poem. For the angels' daily lives are given weight in the piece equivalent to descriptions of the sleeping man; and the lesson the angels impart, that earthly activities bear within them traces of the divine, is applicable in the man's waking life—making it as "real" as anything else.
The soul shrinks
From all that it is about to remember,
From the punctual rape of every blessèd day
There are two interesting facets to this quotation. First, the soul already knows that it will have a memory, in waking life, of the world it sees while the man sleeps––the celestial will carry over into the "normal" return to the world. And second, daily activities are referred to with a jarringly violent term, a "rape" (here, probably, more like an attack or abduction), whereby the "timeliness" and busyness of daily life means that the man, and his soul, have little ability to stop and dwell in beautiful moments. Thus the "blessèd day" carries within it a beauty and bounty that the waking man will have to work hard to recall, by bringing back to mind his soul's journey in the nighttime.
Let there be clean linen for the backs of thieves;
The man returns to life not just with a new picture of the divine, but with a powerful moral commitment. Although the angels have not told him to do anything explicitly, he sees, in their sweet, gentle movements, a new form of charity to be accorded to all the living. Notably, this charity takes the form of laundry, the daily task that he is meant to complete when he awakes. So he wishes not only to wash his own clothes, but to make sure there is adequate and purified clothing even for those whom society has cast away.
