Final answer:
A mother is speaking to her son, utilizing the metaphor of a decrepit staircase for life's difficulties, and imparts the theme of perseverance.
Step-by-step explanation:
In the poem, the speaker is a mother speaking to her son about the difficulties of life and the importance of perseverance. The central metaphor in the poem is the comparison of life to a laborious climb up a decrepit staircase, symbolizing the speaker's ongoing struggles. The theme of the poem is to persevere when life is not easy, as illustrated by the challenges described in climbing the staircase. The quote that best supports this theme is: "Don't you set down on the steps / ‘Cause you finds it’s kinder hard." (Lines 15-16), which encourages continued effort in the face of difficulties.