In Freemasonry, one must take the oath of initiation on the sacred text of one’s particular religious faith, whatever it might be:
For Buddhist Freemasons, a standard text for taking the Masonic oath is the Dhammapada:
The Buddhist hold Holy 31 books that comprise
the Tripitaka, the three baskets which contain the
essence of Buddha’s teaching. Only one is held as
the Volume of Sacred Law – the Dhammapada. It
consists of 423 melodious Pali verses, set out in
26 vargas or chapters and is generally considered
one of the most perfect ethical manuals. Buddhist
sects may find other volumes more important but
the Dhammapada has been accepted by the
Grand Lodge of England and is acknowledged
acceptable for obligating candidates…Freemasonry is non-sectarian and non-doctrinal
in character. We accept men of all faiths and
beliefs who can agree on the moral law – to be
good men and true and men of honor and
integrity.
https://www.mn-masons.org/sites/mn-masons.org/files/Volume%20of%20Sacred%20Law.pdf
Now that I’ve learned Buddhists can become Masons, I might seriously consider it someday.
Freemasons are required to profess belief in a Supreme Being, whatever that being may be:
Freemasonry’s members - FREEMASONS - upon petitioning for membership are required to profess a belief in a Supreme Being. They are not required or requested to elaborate any further on their beliefs except to make a positive affirmation that they have such a belief.
http://www.masonicinfo.com/gaotu.htm
A Buddhist Freemason may regard Buddha-nature, Nirvana, the Buddha, the law of karma, the Dharma, etc. as their Supreme Being for the sake of Masonic initiation, rather than a theistic god.