The entire second stanza of "To the Virgins" is about the sun's "race" (7) through the sky. The farther the sun progresses through the sky, the closer it is to setting. Likewise, the further one progresses through life (the older one gets) the closer one is to the end (death). The speaker doesn't come out and say that, but it's very strongly implied, both in the second stanza and throughout the poem.
- Line 5: The speaker calls the sun the "glorious lamp of heaven." "Lamp" is here a metaphor for the sun, which is like a lamp in that it "lights up" the heavens just like a lamp lights up a room.
- Lines 6: The sun gets "higher" as it progresses from east to west. Have you ever noticed that it looks "low" in the morning, is directly overhead at noon, and is low again when it "sets"? The sun doesn't really "get" "higher"; this is attributing human characteristics (moving up) to a non-human thing (the sun), which is called personification.
- Line 7: The sun isn't a human thing, so it can't really "run" a "race." This is personification again.
- Line 8: The sun doesn't really "set"; the earth rotates. "Setting" is here a metaphor for what appears to happen at the end of the day. Also, "setting" is a human activity, and the sun isn't human; so this is more personification.