On July 2, 1776, the Continental Congress approved the resolution offered by Richard Henry Lee of Virginia. It was seconded by John Adams.
Resolved: That these United Colonies are, and of right ought to be, free and independent States, that they are absolved from all allegiance to the British Crown, and that all political connection between them and the State of Great Britain is, and ought to be, totally dissolved.
The very next day, John Adams wrote to his wife Abigail and predicted for all future generations of Americans how important Independence Day would be.
The Second Day of July 1776, will be the most memorable Epocha, in the History of America.—I am apt to believe that it will be celebrated, by succeeding Generations, as the great anniversary Festival. It ought to be commemorated, as the Day of Deliverance by solemn Acts of Devotion to God Almighty. It ought to be solemnized with Pomp and Parade, with Shews, Games, Sports, Guns, Bells, Bonfires and Illuminations from one End of this Continent to the other from this Time forward forever more.
Adams would be two days off from his prediction, however.
Adams was on the committee of five members of Congress to draft a document setting forth the reasons for independence. Thomas Jefferson was given the task of writing such a document. This Declaration was debated, edited and then, on July 4, 1776, was voted on and approved, a document that eloquently articulated the reasons why the colonies had separated from the British Empire. The Declaration would not be signed until August, however, going forward, America began celebrating Independence Day on the 4th of July.
In a twist of fate, 50 years to the day of passing the Declaration of Independence, Thomas Jefferson and John Adams both passed away on July 4, 1826.