Why does the book compare Sai to the sun and moon only to immediately say the comparison is unfitting?

In Chapter 50, the comparison of Sai Baba to the sun and moon is a poetic device used to emphasize His supreme and unchanging nature. The author points out the inherent flaws in these powerful celestial bodies: "It is not fit to compare him to the sun, for that sun sets. If I compare him to the moon, it wanes." By highlighting the transient and imperfect nature of even the grandest worldly objects, the text powerfully asserts that "Sai is forever complete." This technique serves to elevate Sai beyond any possible mortal or natural comparison, establishing His eternal, perfect, and constant presence, which is a central theme of the devotion encouraged throughout the book.