The poem centers around the atmosphere created by de la Mare. The mood is established early in the poem, and readers immediately feel the loneliness and anxiety of the traveler. This atmosphere is created through the language of the poem to describe the setting, using words such as dark, empty, and listening to make the traveler and the reader feel empty and sad. The poet also repeats certain words, such as knocking and stillness. The anapestic rhythm also adds urgency to the poem, making the traveler feel anxious. After the traveler leaves, the reader is left behind in the desolate setting because the poet is now concentrated on the listeners instead of the traveler. We don't know who the listeners are; we also don't know what promise was made by the traveler. I think this is the beauty of the poem because de la Mare wants us to wonder who we are and what place we hold in the universe (theme). We can't help but personalize the poem.
in my openion,traveller was a kind of messenger of God,who came to guide the men to the right path.nature is responding it one after another and even the supernatural beings welcomed him but the people are so drowned in their sins that not even taking pain to listen to that person.moonlit,sky full of skies showz the blessing of God which He wanted to shower on people but as if they dint listen to the Traveller they left dejected and ,the traveller made nature witness to his duty that he performed it well by knocking twice or thrice.and went back and left that place