What is freemasonry?
At the time of the Crusades, a group of knights pledged themselves to protecting pilgrims to the Holy Lands because pilgrims were being slaughtered on their way there. These knights lived a Holy Order, and they become known as "The Poor Knights of the Temple of Solomon" or, for short, the "Knights Templar." Their practices in the temple did not resemble the practices performed by the Jews in the Temple. They became rich and wealthy and not always so knightly, and eventually they fell.
Later on, in the construction of the great Gothic cathedrals and other impressive structures of the Dark Ages, masons who were free from serfdom came together and worked together, becoming exclusive and creating lodges to talk about their trade. They required a person to be initiated into their ranks. They started claiming ties to the Knights Templar to give themselves credence.
In the Renaissance, many men of reputation wanted entrance into the lodges. Free-masonry was open to all men of learning and wealth who were initiated through their rites and rituals. Their symbols included the compass and the square, and the plumb line, being the tools of masonry and the symbols of the standards they wished to keep. They used secret grips, handshakes, and passwords. These were kept so secret that when a man who was going to publish the secrets mysteriously disappeared and died in America a few centuries later, the popularity of Masonry steeply declined.
Here are some terms and phrases in Masonry that might sound familiar to a Mormon, especially one who has been through the temple for endowments:
"mystic veil which has long been lifted"
"compass and square"
"they put on an apron"
"hat, sash, yoke, and apron"
"brethren will be properly clothed"
"make the sign"
"under no less penalty"
"the left arm...forming a square"
"drop the left arm suddenly"
"Holy Bible, square, and compass"
"raise the hands and drop...repeat three times...(saying) 'O Lord' "
"whispers the password...in the ear"
"confirmation will make it known by the usual sign of the Mason (raise the right hand)"
"those opposed, by the same sign"
"three distinct knocks"
"let him enter"
"should you attempt to reveal the secrets"
"own free will"
"I (state name) of my own free will...in the presence of Almighty God...that I will always hail, ever conceal, and never reveal"
"as the sun rules the day and the moon governs the night"
"by the signs and tokens"
"Has it a name?" "It has" "Will you give it to me?" "I did not receive it."
"a new name"
"deeply impressed upon the mind"
"let us report"
"orders of the priesthood"
"the veils are now pushed apart to admit the candidate"
"the New Era"
So what goes on in the Mormon temples? Many of the rituals and rites are sacred--though the LDS like to say "sacred, not secret."
One of the first and least secretive is Baptisms for the Dead. I performed this one when I was still LDS. A member of the church gets baptized on behalf of someone who was dead who wasn't Mormon (regardless of whatever it was they might have been) so that they can have a chance to be saved in the afterlife. This is especially interesting because the Book of Mormon teaches that there are no more chances after this life (Alma 34:32-25, Mosiah 3:24-27). The only Bible reference to baptizing for the dead is when Paul is speaking of non-believers ("they" vs. "we") practicing it, in trying to convince believers of the resurrection.
The second common ceremony is the Endowment Ceremony, in which patrons are "endowed" with special knowledge. The first part of this ceremony involves a washing, which used to be literal, but which is now symbolic. This is followed by being the garments, which originally were meant to only be worn in the temple, and which have evolved as American culture's modesty standards did. The garments have Masonic symbols sewn on them. A person is then given a secret name, which will act as their password into heaven. Next, they watch a film on salvation. This film used to include a depiction of Satan hiring a Christian minister to deceive people. After this, more symbolic temple clothes are worn, and the person is taught special "signs" and "tokens" which include secret handshakes and arm movements which they will later be "tested" on in a ritual symbolic of entering heaven. This is a very Masonic ceremony. However, some of these stranger ceremonies were removed, particular the penalty ceremony in which temple-goers would represent their own deaths if they revealed the ceremony secrets (removed early 1990's), and an oath which promises to avenge the death of Joseph Smith.
Sealings are where a man and wife, and perhaps their children if they weren't born into a sealed marriage, are sealed together for eternity, in contradiction to the teaching in the Bible from Jesus himself that marriage as we know it on earth will no continue in heaven.
The final ordinance is the second sealing, which is offered to people only by invitation and which guarantees the recipient of the highest degree of glory in heaven. It is not public knowledge whether this is still performed in temples today.
All of this is so Masonic and secret in nature for a couple of reasons. First and foremost, many of these rituals were "revealed" to Joseph Smith after he became a Mason. Even his last words were Masonic: "O Lord, my God, is there no help for the widow's son?" is the Masonic cry for help. Second, none of these are at all like what was done in the Temple of Solomon. Claiming that they are the restored true church but having strange rituals that are not at all Biblical is certainly contradictory to that claim and would probably scare away potential converts who knew the details.