The poem opens with a strange kind of rescue: we are "saved by art," but the thing that saves us does it by "putting us into doubt." Salvation here doesn't mean comfort. Art unsettles us, and that unsettling is the gift. The speaker seems to accept this, even welcome it.
The second couplet turns to images that feel puzzling at first. "All my cake will be dough" runs baking backward, so something finished and sweet becomes raw and unformed again. "Night returned to a wing" does something similar, as if darkness were handed back to the bird it came from. Both images suggest undoing, a return to an earlier, more open state. The title, "Provisions," hints at what we carry with us, and the poem suggests that what we carry may be unfinished material rather than certainty.
The mood is quiet, light, and a little mysterious. It isn't mournful. There's a calm willingness to give up completeness and stay in the questions.