The words "under God" were added to the US Pledge of Allegiance in 1954, during the Cold War, under the Eisenhower administration, to mark a distinction between the USA and so-called 'godless' communism of the Soviet Union and the People's Republic of China.

When people today quote "one nation, under God" as evidence that the founders of this country created a Christian Nationalist country, they are repeating historical inaccuracies. You are welcome to correct them.