It is said that the Sun and the Moon are the eyes of Narayana. The rays of the Sun form the eyes. Each of them, viz., the Sun and the Moon, give strength and heat to the universe respectively.
सूर्याचन्द्रमसौ चक्षुः केशाश्चैवांशवः स्मृताः। बोधयंस्तापयंश्चैव जगदुत्तिष्ठते पृथक्॥