WASHINGTON — President George W. Bush is remembering Martin Luther King Jr. and his powerful words 50 years ago – words that Bush says changed the hearts of millions.

Bush is not attending Wednesday's 50th anniversary ceremony in Washington. A spokesman says the invitation came as Bush was recovering from a recent heart procedure, so he declined.

But Bush and his wife, Laura, say in a statement from Dallas that King's "I Have a Dream" speech challenged the nation to live up to its founding principles that all people are created equal.

Bush said the nation has come a long way – "yet our journey to justice is not complete" and there is still a need to take King's vision to every community in America.

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  • U.S. civil rights leader Martin Luther KIng (C) waves to supporters from the steps of the Lincoln Memorial on August 28, 1963 on the Mall in Washington D.C. (Washington Monument in background) during the 'March on Washington'. (/AFP/Getty Images)

  • More than 200,000 civil rights militants gather on Aug. 28, 1963 on the National Mall in Washington D.C. during the 'March on Washington'. (AFP/AFP/Getty Images)

  • In this Aug. 28, 1963 file photo, President John F. Kennedy stands with a group of leaders of the March on Washington at the White House. From second left are Whitney Young, National Urban League; Dr. Martin Luther King, Christian Leadership Conference; John Lewis, Student Non-violent Coordinating Committee, partially obscured; Rabbi Joachim Prinz, American Jewish Congress; Dr. Eugene P. Donnaly, National Council of Churches; A. Philip Randolph, AFL-CIO vice president; Kennedy; Walter Reuther, United Auto Workers; Vice President Lyndon B. Johnson, partially obscured, and Roy Wilkins, NAACP. (AP Photo/File)

  • This August 28, 1963 publicity photo provided by PBS shows activists during The March on Washington in Washington, D.C. -- from the film,"Makers: Women Who Make America."(AP Photo/PBS, Courtesy Leonard Freed, Magnum Photos)

  • FILE - In this Aug. 28, 1963 file photo, the top of the Washington Monument and part of a U.S. flag are reflected in the sunglasses of Austin Clinton Brown, 9, of Gainesville, Ga., as he poses at the Capitol where he joined others in the March on Washington. (AP Photo/File)

  • U.S. civil rights leader Martin Luther KIng (3rd from L) walks with supporters during the Aug. 28, 1963 "March on Washington." (AFP/Getty Images)

  • In this Aug. 28, 1963 file photo, The Rev. Martin Luther King Jr. waves to the crowd at the Lincoln Memorial for his "I Have a Dream" speech during the March on Washington. The march was organized to support proposed civil rights legislation and end segregation. (AP Photo/File)

  • In this Aug. 28, 1963 file photo, Dorothy Height, right, National President of the National Council of Negro Women and Director of the center for Racial Justice of the national YWCA, listens as the Rev. Dr. Martin Luther King Jr., gestures during his "I Have a Dream" speech (AP Photo, File)