Answer:
Kennedy gives credibility to Martin Luther King Jr. by quoting Martin's poems he had written in the past to inspire others. Ethos being a persuasion factor by giving credibility to the individual speaking. You can see an example of Kennedy’s use of credibility when he quotes “In our sleep, pain which cannot forget falls drop by drop upon the heart until, in our own despair, against our will, comes wisdom through the awful grace of God.” This statement gives emphasis to the presidents point to say that we do not need hatred in this country, rather we can get through tough times like we have before.
Explanation: (evidence found in paragraph 5)