I Have a Dream a speech for a specific time and place

In what ways is "I Have a Dream" a speech for a specific time and place, and in what ways is it universal? Does reading it more than a half century later change its meaning and if so, how? If not, why not?
Be specific, use examples, use at least one-in-text citation (direct quotation, paraphrase, or summary) in each body paragraph, and correctly cite the source.