Anaphora is a rhetorical device where the repetition of a word or phrase at the beginning of successive clauses, sentences, or verses is used to emphasize a point or create a particular effect.
Here are some examples:
* "We shall not fail. We shall not falter. We shall not yield." (Winston Churchill)
* "I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character. I have a dream that one day, right here in Alabama, little black boys and black girls will be able to join hands with little white boys and white girls as sisters and brothers. I have a dream..." (Martin Luther King Jr.)
Let me know if you would like more examples or explanation!