He emphasizes the phrase "now is the time" to bring attention to the fact that it is now time to fulfill the promises.
He develops a sense of urgency with metaphors and similes that show the power of the moment: for instance, by using the metaphor “quick sand of racial injustice… [and] solid rock of brotherhood,” he compares unstable sand to stable rock, delivering the message that the longer Americans allow racial discrimination to be accepted, the deeper in poverty the Negro will sink, unable to escape the “quick sand of racial injustice” (King).
