It has become common practice in the U.S. Congress to provide a variety of texts for ritual oaths of office. The Washington Times reported in January, 2013:
As religions have expanded, so have the options for swearing-in ceremonies.
Both House and Senate lawmakers are officially sworn in on their chamber floors, and then have ceremonial swearings-in for keepsake photos afterward. Members are not required to hold any text at all, merely to raise their right hand and swear — but many do hold something, particularly during the ceremonial oath.
The Library of Congress even provides books to House members who don’t bring their own, and lawmakers can pick them off a table when they enter the ornate room for a one-on-one ceremonial oath with Mr. Boehner.
On Thursday they had nine options: Catholic, Protestant and Eastern Orthodox Bibles, the Torah, the Koran, the Book of Mormon, Hindu Vedas, an ornate box holding Buddhist Sutras, and copies of the U.S. Constitution.