The following is a list of principles and ideals are Christian in origin, yet they are all found in either or both the Declaration of Independence and the U.S. Constitution – documents we are told are supposedly meant to be secular in their nature:
The Providence of God. This means that God takes an active role in the affairs of man, and works His will through them and their actions.
The Law of God: This includes revealed law, but also Natural Law.
The Law of Nations (Article I, Section 8, Clause 10): Derived from Christian thinkers, Grotius, Pufendorf and Vattel by using logical extension of God’s revealed and Natural Law.
The Equality of Man: A Biblical notion based on the fact that all men are created in God’s image.
God-Given Rights: Again, based on the creation of man in God’s image.
Government Secures Rights (not grants them): Based on the Scriptural assertions that God is sovereign, and that He defined the relationship between the governed and government, as well as the proper limits of both civil and religious authority.
Government by Consent of the Governed: God told Moses to have the people select leaders, and Scripture repeatedly says the people elect their leaders.
The Sinful Nature of Man (requiring the checks and balances): This is stated in Genesis. All Socialist systems are based on the notion that man can perfect himself. The founders’ system was based on the Biblical assertion that man is hopelessly flawed and that government should be constructed in such a way as to account for and protect against the avarices of men.
The Three Branches of Government: According to James Madison, this comes directly from Isaiah 33:22 For the LORD is our judge, the LORD is our lawgiver, the LORD is our king; it is he who will save us.
Limited, Delegated Power: God defined the roles that civil government was to play, and set the boundaries outside of which it is not to step.
Rights of Criminal Defendants: Again, defined by God as dictated to Moses. In the Constitution, you will find that in “ties,” the poor man is supposed to be given the decision. This is another Biblical teaching.
Property Rights: Established by God in Genesis and again after the Exodus.
The Sanctity of the Contract (Article I, Section 10, Paragraph (1): A Biblical principle. God makes many covenants with His people, and He even gives them rights in these covenants. If one reads Scripture carefully, one finds that God even gives the people a right to demand of Him — but only if and when they have met every duty of theirs in that covenant first.
Two Witnesses for Capital Punishment (Article III, Section 3, Paragraph (1)): A Biblical principle
No Corruption of Blood (Article III, Section 3, Paragraph (2)): A Biblical principle
Keeping the Sabbath (Article I, Section 7, Paragraph (2)): A Biblical commandment.
So you see, even if the Declaration and Constitution do not specifically mention God (which the Constitution does), they incorporate nearly every aspect of God’s plan for human government. The key here is in understanding that the system God gave to Israel does not work unless the people live their religion in their daily lives. That means God’s system – while not a Theocracy – was also not secular, and neither was the government the founders designed.
THE ROAD TO CONCORD 
That’s a smart way of loonkig at the world.
It’s also what the founders said in their personal letters to each other 🙂