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. You will think me transported with Enthusiasm but I am not. I am well aware of the Toil and Blood and Treasure, that it will cost Us to maintain this Declaration, and support and defend these States. Yet through all the Gloom I can see the Rays of ravishing Light and Glory. I can see that the End is more than worth all the Means. And that Posterity will tryumph in that Days Transaction, even altho We should rue it, which I trust in God We shall not.
John Adams, letter to Abigail Adams, July 3, 1776
I've read that and to this day it sends chills down my spine. If only we had leaders like that now.
The Continental Congress adopted a resolution severing ties with Great Britain on July 2nd, though a formal Declaration of Independence was not adopted until July 4th; which explains John Adams' letter to Abigail, dated the 3rd of July.
From the book "Voices of 1776":
A copy of the momentous document was promptly sent to Washington [fighting] in new york, and July 9 became a special day. As reported in the Pennsylvania Journal:
This afternoon the Declaration of Independence was read at the head of each brigade of the Continental Army...it was received everywhere with loud huzzas and the utmost demonstrations of joy. And tonight the equestrian statue of George III....has, by the Sons of Freedom, been laid prostrate in the dirt - the just desert of an ungrateful tyrant! The lead wherewith the monument was made is to be run into bullets to assimilate with the brains of our infatuated adversaries...