The video that I watched was a snippet of a speech done by Martin Luther king right before he was assassinated. I think in terms of his speech, King boost his credibility by combining his years of experience in advocating with the obvious passion that he is displaying in his speech. His passion I think also allows him to sort of connect with the audience. Due to this connection he establishes with the audience early on his credibility is boosted. All in all the speech was a success.