Why is the "moon" in Moonlit Night on a Spring River the soul of the whole poem? Please give an answer. Thank you ~ ~ ~

The whole poem takes spring, river, flowers, moon and night as the background and the moon as the main body. "Moon" is a mixture of scenery and scenery in poetry. It beats the pulse of the poet, and it is like a bond of life in the whole poem. It runs through ups and downs, touching the scene, and poetry fluctuates with the birth and death of the moon. The moon went through the process of rising, hanging high, setting in the west and setting in the sun overnight. In the moonlight, rivers, beaches, sky, Yuan Ye, maple trees, flower forests, flying frost, white sand, boats, tall buildings, dressing tables, anvil stones, flying geese, diving ichthyosaurs, sleepless women and wandering wanderers form a complete poetic image, showing a picture full of philosophy and life interest. The color of this picture scroll is light and rich. Although sketched in ink and wash, it is "ink in the colorful", showing colorful artistic effects from the complementary of black and white and the coexistence of reality and reality. It is like an elegant China ink painting, which reflects the beautiful artistic conception of the moonlit night by the river.