The first two lines of the poem, "The bright moonlight in front of the bed seems to be frost on the ground," describe the illusion that the poet had in a moment in the specific environment of a foreign country. For a person who lives alone in a foreign country, running around and being busy during the day can dilute the sorrow of separation. However, in the dead of night, it is inevitable that waves of longing for his hometown will arise in his heart. What's more, it's a moonlit night, let alone an autumn night with a frosty moonlight. The word "suspect" in "Suspect is frost on the ground" vividly expresses the poet's confusion when he first wakes up from sleep, mistaking the cold moonlight shining in front of his bed for thick frost covering the ground. The word "frost" is used better. It not only describes the brightness of the moonlight, but also expresses the coldness of the season. It also highlights the loneliness and desolation of the poet wandering in a foreign country.
The last two lines of the poem, "Looking up at the bright moon and looking down at my hometown," deepen the homesickness through the depiction of movements and expressions. The word "wang" echoes the word "suspicious" in the previous sentence, indicating that the poet has turned from daze to sobriety. He stared at the moon eagerly and couldn't help but think that his hometown was also under the shining of this bright moon at this moment. This naturally leads to the conclusion of "lowering my head and thinking about my hometown". The action of "lowering the head" depicts the poet completely in deep contemplation. And the word "thinking" leaves readers with rich imagination: the fathers and brothers, relatives and friends in the hometown, the mountains, rivers, plants and trees in the hometown, the lost years and past events... they are all missed. The content contained in the word "thinking" is really too rich.
This five-character quatrain vividly reveals the poet's inner activities from "doubt" to "hope" to "thinking", and clearly outlines a picture of homesickness on a moonlit night. The language of the poem is fresh and simple, as clear as words; the expression is spoken casually and in one go. But the concept is full of twists and turns. The content of the poem is easy to understand, but the poetic meaning is difficult to fully appreciate.
Hu Yinglin, a scholar of the Ming Dynasty, said: "The quatrains of Taibai are all made up of words. It is said that there is no intention to work but nothing is not done" ("Shisou·Inner Edition").
This poem "Thoughts on a Quiet Night" can be said to be an excellent illustration of the "nature" and "no intention of work but no lack of work" in Li Bai's poetry.