On June 20, 1782, Congress adopts the Great Seal of the United States. Adoption came six years after the Continental Congress appointed the original committee to design a seal. Congress appointed the original committee just a few hours after they adopted the Declaration of Independence, on July 4, 1776.
E Pluribus Unum, Latin for Out of Many, One, was once a de facto motto of the United States. However, it was never codified into law. Thus, In God We Trust is the official national motto.
Our Lost Founding suggests that perhaps the two go hand in hand.
Founding Father and Patriot Charles Thomson’s “Remarks and Explanation” are the only official comments about the symbolism and the meaning of the Great Seal. Here is the portion regarding The Reverse:
“The pyramid signifies Strength and Duration: The Eye over it & the Motto allude to the many signal interpositions of providence in favour of the American cause. The date underneath is that of the Declaration of Independence and the words under it signify the beginning of the new American Æra, which commences from that date.–” (emphasis added)
“The Motto” Annuit Cœptis translates to (Providence) favors our undertakings.
Lastly, Thomson, also a Greek scholar, spent his final years working on an English translation of the Bible.