I need more details to answer this question
Hello. You did not inform the speech to which this question refers, which makes it impossible for it to be answered accurately. However, I will try to help you in the best possible way.
If King was trying to be persuasive, lines 307 - 334 can only affect persuasiveness by reinforcing the argument King is making. This can be done through a clear and objective diction that reinforces the importance of King's words. In addition, these lines can create a logical, ethical or emotional structure for the speeches, proposing a greater connection between king and the public.
a dream is what you hope can come true
