"I have a dream."
The famous words spoken by Martin Luther King Jr. made an impact from the moment they were uttered on the steps of the Lincoln Memorial on Aug. 28, 1963.
The speech, given at the March on Washington for Jobs and Freedom, resonated from beyond the National Mall to the far-reaching corners of the Deep South and across the country, solidifying King as an indelible force to be reckoned with in the civil rights movement.
READ: Martin Luther King's Speech: 'I Have a Dream' - the Full Text
Waving the banner for progress, King did not condemn the ills of hatred and malice that often permeated day-to-day news of racial conflicts with minced words and an angry fist.
Instead, King meshed the cadence of a Baptist preacher with the credence of a man who was well-versed not only in the history of African-Americans in the United States, but America itself.
"I feel like Dr. King's speech is a masterpiece in rhetoric," Rosalind Kennerson-Baty, a full-time lecturer in the communication studies department at Baylor University told ABCNews.com. "He had a masterful way of tugging at the head as well as the heart of those who wouldn't have been able to receive his messages."
As one of the most shining examples of commanding rhetoric, ABC News delved into five reasons that made King's speech one of the most famous in history.
'Five Score Years Ago'
In the speech, King incorporated quotations from patriotic and religious documents to put the struggle of racial inequality "in the context of the great principles of American history," said Keith Miller, an associate professor of English at Arizona State University, whose research focuses on the rhetoric and songs of the civil rights movement.
King pulled phrases from the Declaration of Independence, the Emancipation Proclamation and even the song "America (My Country, 'Tis of Thee)" to drive his points home, Miller said.
"He's appealing to the most sacred touchstones that there are in the United States," he told ABCNews.com. "He's incorporating these other voices that are more or less unimpeachable."
"He's saying, 'Hey, this is the rhetoric upon which our country was founded,' Kennerson-Baty said. "These political documents were forged so that we have a system of sustainability that outlined humanity, but also the political rights that have been given to all of God's children."
These historic documents come alive throughout the course of King's speech. In a way, he appropriated the texts to begin writing a new chapter in history, said Taj Frazier, an associate professor of communication at the University of Southern California.
"His ability to appropriate these historic analogies or phrases really spoke to his ability to utilize history and make [these themes] applicable to that particular moment," Frazier said.
'Exile in His Own Land'
But even as King adapted the words of weighty historical texts, he also drew from the Bible in the "Dream" speech, focusing particularly on the tales that mirrored the political climate of the 1960s.
Miller said that King used the Bible and especially the books of Exodus, Isaiah and Amos to chart the course of the civil rights movement in many of his speeches. The "Dream" speech was no exception.
"The country, especially at this time, was very Judeo-Christian. The Bible is this very, very authoritative document in the minds of millions and millions of people," Miller said. "King is using the Bible to argue against segregation."
"He tries to cast it in the arc of this great historical narrative and elevate the American civil rights movement to parallel Exodus," Miller said of the speech's scriptural leanings. "So [the speech] is a revamping of Exodus, or a later chapter of the Exodus."
Kennerson-Baty said King's religious emphasis, likely derived from his training as a minister, "transcends the dirt roads of the Southern, black, Baptist church" to resound on a national scale.
"The commentary of the time marked King as the Moses that would bring this generation of people fighting for civil rights," she said. "It makes you connect, not just on a socio-political level, but also a spiritual level. That's the strongest cross-cultural element of the speech."
'We Can Never Be Satisfied'
King also used traditional rhetorical devices that enhanced the power of his words -- particularly his use of repetition, which highlighted the points he wanted to resonate with audiences, according to Kennerson-Baty.
"If you think about it -- the average attention span of any adult person is probably a good 10 to 15 minutes. The speech wasn't much longer than that," she said.
Most people may be most familiar with King repeating "I have a dream" during the speech, but it isn't the only phrase he consistently hammered upon. He made the audience aware he is on the National Mall "100 years" after Lincoln stood before him, and that his message was to "let freedom ring."
Miller said King's speech was marked with repetition, rhymes and parallelism to make it easier for both the speaker and the audience to remember.
"It also helps to build the cadence in his delivery," he said. "It's easier for people to follow, and you become more rhythmical and emphatic."
But both Kennerson-Baty and Miller agreed that King's repetitiveness also came from his religious background.
"Repetition comes out of preaching that started from slavery," Miller said. "Most slaves were forbidden by law to read or write. If you were a slave, you had to pick up religion from sermons and songs. If you were a preacher, you had to remember the sermon yourself and wanted everyone in the audience to remember it, too."
"The preacher's orontundity of this speech, it takes it back to religiosity," Kennerson-Baty said. "It speaks to people who look like him, have similar experiences at the church. You have a responsibility as a speaker to use language that connects with the human experience."
'Let Freedom Ring'
Not only do King's words stand alone, but the way in which he delivered them merited recognition.
"The 'I Have a Dream' speech is iconic as his identity," Kennerson-Baty said. "He put his mind, his soul, this movement where his mouth was. This is beyond rhetoric."
But Miller was quick to shoot down allegations King extemporized the speech in the shadow of Abraham Lincoln 50 years ago.
"Nobody would try to extemporize on that occasion -- 250,000 people on the National Mall watching you. The whole country, the whole world watching you on TV," he said. "African-American orators didn't get opportunities like this every day. To try to depend on immediate inspiration would be foolish."
Instead, Miller said it was likely King had the lines of his speech pretty close to memorized, which was why he commanded the throngs.
"That's why his delivery always sounds so good: He's got the lines memorized or close to memorized," he said. "He's kind of like an actor in a play. The actor is not thinking about the lines -- the actor has memorized the lines, the actor is only thinking about the delivery."