Answer:
Repetition is a literary device that makes an idea or message clearer by using it continuously.
It can also be used as a rhetorical device; a word, line or sentence repeated to make its significance in the whole text more emphatic.
From the poem above, the poet uses repetition of the word "If" to emphasizes the need for calm.
"If you can wait and not be tired by waiting," from line 5 shows that the author believes there is a reward if we meet a certain requirement.
Reads like a martin luther king or like minded speaker going for freedom of speech and struggle for justice (against the apartheid that Rosa Parks also stood - or in her case literally sat - for). "Mississippi Burning" is a very powerful film.
Weak is the most opposite meaning to tenacious.