How does repetition of the phrase "we must” help Roosevelt achieve his purpose?

Excerpt from “we shall overcome” by lyndon b. johnson read these sentences from the speech. the issue of equal rights for american negroes is such an issue. and should we defeat every enemy, and should we double our wealth and conquer the stars, and still be unequal to this issue, then we will have failed as a people and as a nation. for, with a country as with a person, "what is a man profited if he shall gain the whole world, and lose his own soul? " how do these sentences convey johnson’s viewpoint? a. johnson feels that america must use its military and economic strength to ensure equal rights around the world. b. johnson believes that no matter how much the nation accomplishes, the gains will be meaningless until all americans have equal rights. c. he believes that in modern societies, there will always be some groups that feel more equally treated than others. d. he thinks that because the nation has already achieved so much, it should be easy to ensure that all americans are treated equally.