At his own request, President Barack Obama ended his inauguration oath with "so help me God," even though the phrase is not constitutionally nor legally required. Obama also used two Bibles during the swearing-in, one from Lincoln and one owned by Dr. Martin Luther King, Jr.
According to CNN, historians argue over who was first to use "so help me God" in the oath; the Library of Congress says George Washington used it in his inaugural acceptance, and Abraham Lincoln said it spontaneously in 1861, inspiring other presidents to do the same. Atheist representatives have attempted to legally remove the use of a Bible and the phrase "so help me God" from the oath since 2009 but have been unable to do so.
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