"I pledge allegiance 
to the flag of the 
United States of America, 
and to the republic 
for which it stands, 
one nation
 under God
, indivisible, with liberty 
and justice for all."


Definition Of The Pledge:
The Pledge By Definition



The U.S Flag Code 
The Pledge of Allegiance to the Flag should be rendered by standing at attention facing the flag with the right hand over the heart. When not in uniform men should remove any non-religious headdress with their right hand and hold it at the left shoulder, the hand being over the heart. Persons in uniform should remain silent, face the flag, and render the military salute.
Per U.S. Code Title 4, Chapter 1: Section 4;
Pledge of allegiance to the flag; manner of delivery


History of the Pledge
The Pledge was written by Francis Bellamy in August 1892 and was published in Boston's "Youth's Companion" magazine in the September 8th, 1892 issue.
By Proclamation of President Benjamin Harrison, The Pledge was formally recited for the first time on Columbus Day, October 12th, 1892.  It was recited by 12 million school students to commemorate the 400 year anniversary of Columbus' voyage.
The National Flag Conference adopted the Pledge as part of the National Flag Code on Flag Day, June14th, 1924.  On June 22nd, 1942, Congress passed a joint resolution to approve the U.S. Flag Code which was amended on December 22nd, 1942, and signed into effect by Franklin D. Roosevelt.
The Pledge has been revised over time since it's original version in 1892.  The most recent change, resulting from a campaign by the Knights Of Columbus and other religious leaders, along with the prospect of atomic war, influenced the addition of the phrase "under God" in 1954 by Congress under direction of Dwight D. Eisenhower.
Historical Versions of the Pledge
(Changes in Red)
1892
"I pledge allegiance to my flag and the republic for which it stands, one nation indivisible with liberty and justice for all."

1892 to 1923
"I pledge allegiance to my flag and to the republic for which it stands, one nation indivisible with liberty and justice for all."
("to" was added to an original Pledge publication by Bellamy in October 1892 )

1923 to 1924
"I pledge allegiance to the flag of the United States and to the republic for which it stands, one nation indivisible with liberty and justice for all."
(Changes from "my" flag to "the" flag and the addition of "of the United States" were added as a result of the first National Flag Conference in 1923; lead by the American Legion and the Daughters Of The American Revolution)

1924 to 1954
"I pledge allegiance to the flag of the United States of America, and to the republic for which it stands, one nation indivisible with liberty and justice for all."
("of America" was added at the following years Conference)

1954 to Present
"I pledge allegiance to the flag of the United States of America, and to the republic for which it stands, one nation under God, indivisible, with liberty and justice for all." 
("under God" was added in 1954 by Congress under Dwight D. Eisenhower; a result of a campaign by the Knights Of Columbus and the prospect of war)


"In this way we are reaffirming the transcendence of religious faith in America's heritage and future; in this way we shall constantly strengthen those spiritual weapons which forever will be our country's most powerful resource in peace and war."
 
-Dwight D. Eisenhower