is the Royal Arch open to candidates of all faiths or does it require a Christian belief

Belief in a Supreme Being is required of candidates, but the Order is inclusive of all faiths rather than requiring a Christian belief, as stated on the United Grand Lodge of England's website. An article on the United Grand Lodge of England's website notes that the Royal Arch draws on the Old Testament in a non-dogmatic way, which sets it apart from explicitly Christian orders.

In contrast, Christian companion bodies—such as the Knights Templar and the Red Cross of Constantine—require candidates to be Trinitarian Christians while also holding membership in the Royal Arch, as outlined on the Mark Masons' Hall website.

When a candidate is not Christian, the obligation is taken upon the Volume held by his particular creed to impart sanctity and to be binding upon his conscience, as an article on the Grand Lodge of India's website notes.

In Royal Arch symbolism, the Book of the Law represents the divine will, which must be recovered as a precedent to discovering truth 1. Tradition within the Order connects this symbol to the scriptures lost during the Babylonian captivity and discovered during the building of the second Temple 1. Regardless of historical debate among biblical scholars concerning Ezra's restoration of the texts, the Masonic symbolism treats the recovery of the sacred volume as the ultimate reward of restored freedom following captivity to error 1.