Before this time the coins and notes in circulation bore no overtly Christian references; however, the increased religious feeling during the American Civil War led to many appeals landing on the desk of the Secretary of the Treasury, Salmon P. Chase, requesting that the country’s currency show some reference to God. Other coins were also redesigned to carry the inscription, ‘In God We Trust’, which eventually became the motto of the U.S.A. in 1956. The following year the motto appeared on bank notes for the first time.
While the motto continued in usage until the current day, the two-cent coin did not fair so well. It was only produced for ten years. You can read about the rise and fall of the two cent piece at the Coin Community web site. Also, the U.S. Treasury web-site includes a page telling the history of the ‘In God We Trust’ motto.