?What does it mean to be next door to the east and to the west? What's the allusion?

Original source of the allusion: "A Girl Plowing in the Fields" by Dai Shulun of the Tang Dynasty: "The flowers in the east neighbor's house in the west are all gone, and the wife's clothes are full of tears when she cherishes her beauty." The meaning of the idiom: the neighbors who live on the left and right. Idiom phonetic notation: ㄉㄨㄙㄌㄧㄣˊ ㄒㄧㄕㄜˋ Common pinyin: dōng lin xī she Pinyin abbreviation: DLXS Frequency of use: General idiom Number of words in the idiom: Four-character idiom sense*** Color: Neutral idiom Usage of the idiom: Eastern Neighbors, used as subjects, objects, and attributives; refer to neighbors on the left and right. Idiom structure: Joint idiom Synonyms: Neighbors on the left and right Idiom examples: Those neighbors in the east and west heard the cry and came to watch. Volume 29 of "Eternal Words to Awaken the World" by Feng Menglong of the Ming Dynasty