That's secular progressive bullshit.
The Declaration has many references to God throughout the document. The most famous one is that men are endowed by their Creator with certain unalienable Rights.
“We hold these Truths to be self-evident, that all Men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the Pursuit of Happiness."
The declaration also mentions "Laws of Nature and of Nature’s God”, "Appealing to the Supreme Judge of the World”, and "With a firm Reliance on the Protection of Divine Providence."
The Constitution also honors the Christian Sabbath. The President was given 10 days to sign a bill into law. The counting of the 10 days does not include the Sabbath. This is found in Article 1, Section 7, and Clause 2 which in part follows:
“If any Bill shall not be returned by the President within ten Days (Sundays excepted) after it shall have been presented to him, the Same shall be a Law."
When the Constitution was completed on September 17, 1787, it was signed by the delegates then to be ratified by the states. The delegates signed the Constitution in the “
Year of our Lord.” This is a direct reference to Christianity. This is found in Article 7 which in part follows:
“Done in Convention by the Unanimous Consent of the States present the Seventeenth Day of September in the
Year of our Lord one thousand seven hundred and Eighty seven and of the Independence of the United States of America the Twelfth In witness whereof We have hereunto subscribed our Names, GO WASHINGTON–Presidt. and deputy from Virginia”
Then there's the The Paris Peace Treaty of 1783. The Paris Peace Treaty was the document which formally ended the Revolution and granted the United States independence from Great Britain. In a real sense, the United States formally became a nation on September 3, 1783.
When the United States became a nation, it was done in the “name of the most holy and undivided Trinity.” The preamble to this Treaty states it is based upon the “Holy and undivided Trinity.” The concept of the holy Trinity is unique to Christianity. This statement means the United States was founded on the Christian faith.
The God of the Bible is whom the United States is based upon. The unalienable rights of life, liberty and pursuit of happiness come from the Judeo/Christian God and no one else. He is the Rock of our Republic.
Psalm 18:2 The LORD is my rock, and my fortress, and my deliverer; my God, my strength, in whom I will trust; my buckler, and the horn of my salvation, and my high tower.
There are countless other references to a Christian God in the writings of George Washington, Thomas Jefferson, Benjamin Franklin, Samuel Adams, John Adams, Alexander Hamilton, James Madison, John Hancock, and Thomas Paine.