Brahma Sutras 10.18

अत एव चोपमा सूर्यकादिवत् ॥

ata eva cha upama suryakadivat

And for this very reason the comparison is made to the sun and its reflections.

इसी कारण सूर्य-प्रतिबिम्ब आदि की उपमा दी जाती है।