There have always been many explanations for the origin of this sentence

Buddhism's "Huayan Sutra": "The Buddha's soil grows five-colored stems, one flower and one world, one leaf and one Tathagata." The Buddha said: One flower One world, one tree and one floating life, one grass and one heaven, one leaf and one Tathagata, one sand and one bliss, one square and one pure land, one smile and one worldly connection, one thought and one tranquility. "Buddhist Scripture": "One sand is one world, one flower is one paradise." The volume of "Brahma Net Sutra" says: Lusena Buddha sits in a thousand-leaf lotus, and thousands of Sakyamuni Buddhas are transformed, each living in the thousand-leaf world. The Sakyamuni Buddha in each leaf world has transformed into tens of billions of Sakyamuni Buddhas, sitting on the Bodhi tree. "Ksitigarbha Bodhisattva's Original Vow Sutra": The Buddha told Manjushri, "For example, in the three thousand great thousand worlds, all the vegetation, jungles, rice, hemp, bamboo and reeds, and the dust on mountains and rocks." One thing, one number, makes one Ganges. One Ganges sand, one sand one boundary. Within one realm, one dust and one calamity. In one calamity, all the accumulated dust will be converted into calamity. Tang Wo sent an inscription on the Three Smiling Courtyard Couplet of Donglin Temple in Lushan Mountain: The bridge spans the Tiger River, the three religions have three origins, and the three people have three laughing words; the lotus blooms in the monk's house, one flower and one world, one leaf and one Tathagata. "The Diamond Sutra, Chapter 2": "The sands of the Ganges are equal to the sands of the Ganges. One sand is in one world. All living beings have one mind. Then there are several kinds of minds. The Tathagata has pure five eyes. They can all be seen and known." "The Great Explanation of the Sutra Sutra": "There are hundreds of thousands of millions of monks in the world, and there are so many worlds in one river." "Quotations of the New Zen Master Huanglong Dieshin":

Send a Zen monk with an alms bowl

The harmonious spring scenery is absolutely fine. Five leaves bloom and seven leaves bloom. Within the child, there are branches and fruits. One flower and one leaf come together. "Guanglu by Zen Master Fohai Xiantang": "One flower and one leaf is the Tathagata. One Buddha returns to the earth in one moment." "Volume 37 of the Sleepwalking Collection of the Old Man of Hanshan": Huaidu Thousand Buddha Temple Recalling the Thousand Flowers and Seven Treasures Terrace. One flower and one leaf come together. I don’t know if I have spent enough time with Buddha recently. It's like the shock to Fa Lei back then.