This question is more about American history, but it involves God also. How did the motto "In God We Trust" come to appear on United States currency?
I'll answer your question by quoting from a United States history book, published by A Beka Book Publishers:
It was during the Civil War that the motto "In God We Trust" first appeared on United States coins. The man most directly responsible for the adoption of the motto was Secretary of the Treasury, Salmon Chase. Early in Chase's tenure as secretary of the treasury, a clergyman had written to him suggesting that American coins ought to bear a motto demonstrating the nation's tradition of dependence on God. In response to the suggestion, Secretary Chase sent the following memo to the director of the mint:The clergyman who wrote to Salmon Chase was sharing a Bible doctrine. "Some trust in chariots and some in horses, but we trust in the name of the LORD our God. They are brought to their knees and fall, but we rise up and stand firm" (Ps. 20:7-8 NIV). "The horse is made ready for the day of battle, but victory rests with the LORD" (Prov. 21:31 NIV).
"No nation can be strong except in the strength of God, or safe except in His defense. The trust of our people in God should be declared on our national coins. You will cause a device to be prepared without unnecessary delay with a motto expressing in the fewest and tersest words possible this national recitation."
The director of the mint composed several mottos and Chase chose "In God We Trust." In April 1864, an act was passed authorizing the issuing of a two cent piece bearing the motto. Later, other coins were issued bearing the words "In God We Trust."
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