In this document, EMFJ claims that Freemasonry is deistic.
Deism was a popular religious philosophy in the 17th and 18th centuries, and it was the official "religion" of the French Revolution. It states that all religions actually worship the same god, simply using a variety of different names for him. As a consequence, all religions are equally valid, equally true, and equally good ways to salvation. In this, Deism clearly contradicts Christianity.
The common British-American systems require belief in a Supreme Being from those who are to become members, but it makes no statement about the relative truth of these religions. This policy has two points:
1.) Friendship and understanding is possible between people from different religions. We do not have to deny our own faith, nor do we have to give up the exclusive claims of Christianity, to become members of a brotherhood with people from different faiths. I would not hesitate to play football in a team containing Jews, or work for a charity where some members are Moslems. Would you?
2.) Belief in God is, according tho Masonic tradition, a prerequisite for true morality. As Dostoyevsky wrote: "Without God, all things are permissible". Only he who believes in the existence of an all-seeing God and the reality of divine retribution, will avoid committing the kind of sins for which there are no legal punishments in human society, most importantly the sins of breaking one's promises and betraying what has been said in confidence.
I quote from the home page of the United Grand Lodge of England:
"Although all Freemasons are required to profess and continue in a belief in a Supreme Being, and their ceremonies include prayers, Freemasonry is not in any way a substitute for religion. It has and can have no theological doctrines, it offers no sacraments, and it does not claim to lead to salvation. By having prayers at its meetings Freemasonry is no more in competition with religion than, say, having a meal at which grace is said."
Historically, there is no question that Jews and Moslems do believe in the same God as Christians, even though their understanding of Him is -- from a Christian viewpoint -- flawed. Standing in prayer to God the Father with them is not against my faith. Indeed, there are certain "liberal Christians" with whom I would hesitate more to pray, because even though that prayer might be said in the name of Jesus, I would know that they do not truly believe in Him.