The sun represents the power, order, and goodness of God in Wheatley's poem.
Wheatley asks for the light of God to shine on her as the true sun she revolves around, just as the earth revolves around the sun. Yet while the sun is powerful, a "vast machine" and is "twice forty millions in ... height," it is just a "point," or speck, to God.
Wheatley shows how important the sun is to the all life on the earth, noting that God's "wisdom" is shown in the way the sun is perfectly ordered: without its rays, the earth would be destitute and exist in darkness, yet God also makes sure its heat is not too intense. In lines that seem to presage climate change, Wheatley describes how, were the sun not regulated by God's perfect harmony, it would burn up the earth:
What dire contagion taint the burning skies?
What pestilential vapours, fraught with death,
Would rise, and overspread the lands beneath?
The sun awakening every morning renews what is fair and good, which is all of earth's nature that God means to spring to life.
Wheatley thus shows the sun as a metaphor for God: the sun, like God, is the source of light and light, of harmony, goodness, and beauty, the sustainer of the earth. She also makes sure the comparison emphasizes the grandeur of God. The sun seems mighty and all-powerful to humans, but God is infinitely larger and more powerful. God is the source behind the sun's light and power. God is what we worship rather than the sun.