What is the metaphor in Stopping by Woods on a Snowy Evening?

The repetition of lines 15-26 in the conclusion to the poem indicates that the idea contained in it is highly significant. Although the speaker may literally have "miles to go," the line also functions as a metaphor. He has much life to live before he can "sleep" permanently in a "dark and deep" woods. These lines suggest that although death may at times be more attractive than life to the speaker, he is nevertheless determined to choose life.