Sylvia Plath's poem expresses a deep sense of struggle with loneliness and sorrow. The speaker reflects on their role as a protective barrier, akin to a wall that shields against the harsh elements of life, such as the wind and the cold moonlight. There is a profound yearning for comfort and longing for a respite from emotional pain. The act of providing shade and shelter symbolizes the speaker's desire to alleviate suffering, both for themselves and others.

However, the persistent 'voices of loneliness' suggest an inescapable nature of these feelings, which remain despite their efforts to provide comfort. The lullaby mentioned seems insufficient in softening these feelings of isolation and sorrow. Ultimately, the poem captures the tension between the desire to protect oneself and others from pain, and the reality of feeling overwhelmed by one's own emotions.