The history:
President Eisenhower had been baptized a Presbyterian very recently, just a year before. He responded enthusiastically to Docherty in a conversation following the service. Eisenhower acted on his suggestion the next day and on February 8, 1954, Rep. Charles Oakman (R-Mich.), introduced a bill to that effect. Congress passed the necessary legislation and Eisenhower signed the bill into law on Flag Day, June 14, 1954.[44] Eisenhower said:
"From this day forward, the millions of our school children will daily proclaim in every city and town, every village and rural school house, the dedication of our nation and our people to the Almighty.... In this way we are reaffirming the transcendence of religious faith in America's heritage and future; in this way we shall constantly strengthen those spiritual weapons which forever will be our country's most powerful resource, in peace or in war."
https://en.wikipedia.org/wiki/Pledge_of_Allegiance