The poem opens with what is most likely an allusion to the Bible: "When Jesus spoke again to the people, he said, 'I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life.'" (John 8:12) The speaker introduces the poem as a kind of counterpoint to "the light of life," instead saying that what is to follow is "the light of the mind."
She goes on to describe this light as "cold and planetary," and then paints a stark, icy scene: black trees, blue light, grief-stricken grasses. There is a shortness to her descriptions; the statements are not long and winding but terse, to-the-point. In fact, the sentences in this stanza never stretch across more than two lines, and that lack of elaboration, along with the descriptions of coldness and grief, help set the tone of the poem.
It becomes clear pretty quickly that the speaker has a fraught relationship with religion. Aside from the opening allusion, she also compares herself to God and the grasses to those who would worship and pray to God. More than anything, this image illustrates the speaker's feeling that there is no one above her that she can turn to—she likely compares herself to God not because she feels powerful or adored but because she feels utterly alone, as if there is nowhere she can unload her own griefs.
Lines 3-4 ("The grasses unload ... humility") contain a great deal of consonance that affects the tone of the passage. The repetition of /g/ sounds in particular with "grasses," "griefs," and "God" creates a kind of guttural, lump-stuck-in-throat kind of feeling which evokes the speaker's own grief.