Final answer:
The theme of 'Mother to Son' is about persevering through life's challenges, employing a central metaphor of a difficult staircase to represent life and recommending continual effort and resilience.
Step-by-step explanation:
The theme of "Mother to Son" by Langston Hughes is perseverance through adversity, which is developed through the use of figurative language, particularly metaphor. The character of the mother describes life as "no crystal stair", using a metaphor to depict life's hardships as opposed to an easy, flawless ascent. The "tacks" and "splinters", and "boards torn up" contribute to this metaphor by offering vivid imagery of obstacles and discomfort. When the mother advises her son not to "turn back" or "set down on the steps", she uses the journey up the stairs as a symbol for life's journey, illustrating the importance of resilience and ongoing effort.