is the royal arch open to candidates of all faiths like the craft

Admission into the Royal Arch is open to candidates of every religious creed, provided they profess a personal belief in the Supreme Being 2. This requirement of faith is the primary condition of membership and admits of no compromise, as the United Grand Lodge of England states, maintaining the same broad non-sectarian framework established in Craft Masonry.

Because the Royal Arch operates as the completion of Craft Masonry rather than a detached entity 21, eligibility relies entirely upon a candidate's standing in the Craft. A brother must first be a Master Mason before he may be admitted into a Chapter 1, a step that may be taken four weeks after being raised, as an article on the Grand Lodge of India's website notes.

To ensure that solemn obligations remain binding upon the individual conscience, every candidate takes his obligation on the Bible or on the Volume of Sacred Law held by his particular creed to impart sanctity to his promise, as the United Grand Lodge of England records. The Order requires no adherence to any specific religious tradition, welcoming men of all faiths who acknowledge the Supreme Being.

Historically, the degree was not always understood or practiced as strictly universal. Early Masonic charges show that Masons were originally charged to comply with the Christian usages of the countries where they worked, before the broader requirement to adhere to the non-sectarian religion in which all men agree was formally established 2.

During the nineteenth century, the extent of this universality remained a subject of active debate among Masonic scholars, who divided between a Christian school and a universal school of thought 2. As the Order expanded globally, particularly in India among Parsee, Hindu, and Muslim brethren, writers such as H. J. Whymper questioned whether the existing framework adequately accommodated non-Christian members, while others, like A. F. A. Woodford, argued that Christian and universal interpretations could co-exist peacefully within the fraternity 2.

In modern practice, the Royal Arch maintains a broad universal requirement of belief in a Supreme Being, operating as open to candidates of all faiths and explicitly distinguishing itself from appendant Christian orders that require Royal Arch membership as a prerequisite, as Mark Masons' Hall notes.

The Volume of the Sacred Law is an essential symbol in the Royal Arch, representing the divine will and the recovery of truth lost during captivity 2. In modern practice, every candidate takes his obligation either on the Bible or on the Volume held by his particular creed to impart sanctity to the promise [ugle.org.uk]. Where a candidate does not hold faith in the Bible, he takes his oath of secrecy on the Volume he considers sacred, rendering it binding upon him [grandlodgeofindia.in].

The library sources supplied for this question do not record the historical development or exact dates regarding when candidate obligations on alternative Volumes of the Sacred Law were first introduced in Royal Arch Chapters, focusing instead on the symbolic recovery of the Book of the Law 2.

Early Masonic writers and scholars treated the Royal Arch as explicitly Christian in its origins, symbolism, and doctrine.

Thomas Dunckerley's version of the Royal Arch ritual included explicit Christian doctrine, describing the foundation stone as an allusion to Jesus Christ as the corner-stone of human immortality 3. Colonel McLeod Moore held that the earliest Royal Arch rituals inculcated Christian doctrines in the chapters formed around the middle of the eighteenth century 3. Dr. George Oliver similarly maintained that the original character of the degree was Christian, quoting from Dunckerley's manuscript to support his view 3. E. T. Carson likewise argued that the retained features of the ritual betray its Christian origin 3.

Masonic scholars also identified a Trinitarian character in the degree's central symbolism. H. J. Whymper maintained that the symbolism of the Royal Arch is Trinitarian, pointing to the ancient use of the Delta to symbolise a Triune God 4.

In symbolic interpretation, Walter Leslie Wilmshurst observed that while modern Masons often limit scriptural references to the Old Testament out of a desire for non-sectarian harmony, the Royal Arch allegorises profound spiritual truths that parallel Christian theology 1. He argued that the ritual's central symbol represents the Incarnation, corresponding directly to the phrase "He came down from heaven, and was incarnate" in the Christian Creed 1. Furthermore, he equated the spiritual progression of the Royal Arch—following the mystical death of the Master Mason degree—to the Ascension into heaven 1.