Two short stanzas, two arrivals, two departures. Dickinson builds the poem on a simple pattern: something comes, and it will go. What she never says is who "thou" is. The poem opens with snow, so winter is the obvious guess, and the details of leaving (thawing ground, a crow, the sound of gladness) fit a season turning. But the second stanza swaps snow for "fear," and that word stretches the address beyond weather. Judging by the language, the visitor could be winter, or any bleak spell that arrives in dread and has to be endured. The poem leaves this open, and the openness is much of its power.
The central idea is that the way something arrives does not decide the way it leaves. What enters in cold and fear is promised a departure full of joy, and it leaves behind something valuable: "depth."
The first stanza builds that departure from three small images. The ground is "resuming," a word that suggests the earth had been paused, like work set down for the winter and picked up again at the thaw. Then comes "the sweet derision of the crow," a phrase that holds a contradiction. Derision is mockery, and sweet is its opposite in tone. The crow is hardly a songbird, so its harsh call becomes a cheerful heckling of the departing guest. Last is "Glee's advancing sound," where the capital letter turns an emotion into a figure marching closer. Together the ground, the crow and Glee form a small procession seeing the visitor off, and the word "with" in "go with the resuming ground" makes the exit feel accompanied rather than lonely.
The second stanza turns the seasonal picture into something more personal and more strange. "At such a gait of joy" gives the departure a walk, even a skip. Then the grammar bends: "That man anew embark to live / Upon the depth of thee." "Man" has no article, so it means humankind in general, and "embark" is in the subjunctive, a wish or a possibility more than a plain fact. The metaphors also collide. To embark is to board a ship, and depth belongs to water, so people set out to live *upon* the very thing that frightened them. I read this as a suggestion that a hard time, once over, becomes the medium that carries life forward, though the poem never explains itself so plainly.
The sound of the poem supports this. The lines are short and mostly iambic. The opening line, "In snow thou comest," runs only five syllables, abrupt as a knock at the door, and the dash after "comest" makes the arrival hang in the air before the promise answers it. The first stanza has a clear rhyme in "ground" and "sound," which gives the thaw a feeling of settling. In the second stanza, "joy" and "thee" do not rhyme, and the poem ends on the open vowel of "thee" with no click of closure. That fits the idea of embarking, since the ending points forward instead of tying things off.
The tone is unusual too. "Thou comest" and "thou shalt go" sound like scripture, and "shalt" is the language of decree. Yet the speaker is not pleading with the visitor or begging it to leave. She is telling it, calmly and with authority, what will happen. Addressing a fearful thing in the formal voice usually kept for something powerful, and then giving it orders, quietly reverses who holds the power.
Dickinson left most of her poems untitled, so the first line stands in as the title here, which suits a poem so concerned with beginnings. Its significance lies in how much consolation she packs into eight short lines without sentimentality. The crow's "derision" keeps the comfort from turning sugary, since even the relief has an edge of mockery. And by never naming the visitor, the poem lets readers fill the word "thee" with their own winter, whether a season, a fear or a stretch of life they hope to leave behind.