One version of the story about the origin of the Alevi cem ceremony, as recorded in the essay When the Prophet Went on the Miraç He Saw a Lion on the Road, by Dr. Vernon Schubel, from the book The Prophet's Ascension: Cross-Cultural Encounters with the Islamic Mi'raj Tales, published by Indiana University Press. 

One day while Hz. Muhammad was going on the miraç, suddenly a lion (aslan) appeared on the road. The lion suddenly began to roar.

Muhammad wondered what to do, when all of a sudden a voice called out, "O Muhammad, put your ring in the lion's mouth."  

Muhammad did as he was told and put his ring in the lion's mouth. As soon as the lion took this sign, he became calm. Muhammad continued on his way. He ar­rived at the highest level of the heavens. And there he met with his Friend (Dost).  He spoke ninety thousand words with him:  thirty thousand of these were about the şeriat (Islamic law) and were sent down to the believers. The remaining sixty thousand stayed secret with 'Ali.

In paradise (cennet), food came to Muhammad composed of honey, milk, and apples. These foods were especially chosen. For human beings milk and honey each have a hundred benefits. As soon as apple is added to them, a thousand benefits are found in these three foods. The honeycomb represents the essence of the human being; the breast, from which milk comes, is the womb of the mother; and the peel of the apple is a person's skin. God has bestowed affection on milk, love on honey, and friend­ ship on the apple, and He sent all three of these as the food of paradise to humans.

While Muhammad was returning from the miraç he saw a dome in the city. This dome attracted his attention. He walked up to it and came to its door. The people inside were conversing with each other. They were engaged in conversation (sohbet). Hz. Muhammad knocked on the door in order to go inside. A voice came from within:

"Who are you, and why have you come?" it asked.

The Prophet replied,  "I am the peygamber  (Prophet).  Open up and let me in. Let me see the beautiful faces of the erenler (saints)."

From inside they said, "A peygamber will not fit among us. Go and perform your prophethood (peygamberlik) for your community (iimmet)."

At that the Prophet went away from the door. Suddenly a voice came from God
(Tann). It commanded, "O Muhammad, go back to that door."

According to this command of God, Muhammad once again went to the door and knocked.

"Who is it?" they asked again from inside.

He replied, "I am the peygamber. Open up and let me come in. Let me see your blessed faces."

They said, "There is no room among us for a peygamber. Besides, we have no need of a peygamber. "

The Envoy (Elri) of God, on hearing these words, again turned away. Before he had gone very far, a voice came from God commanding, "O Muhammad, go back. Where are you going? Go and open that door."

The Messenger of God again went to the door. He knocked on the door with its knocker. From inside a voice came asking, "Who are you?"

He replied, "I am the son of a poor man who came from nothing. I have come to see you. Is there permission for me to enter?" He didn't tell them that he was the same person returning again.

At that moment the door opened. Those inside said, "Hello, welcome, good fortune to you. Let your coming be blessed." And they called him inside.

In that gathering (meclis) the Forty were seated and speaking among themselves. The Prophet said, "The holy door, the door of blessings, has opened." Saying, "In the name of God, the compassionate, the merciful" (bismillah-ar­rahman-ar-rahim), and placing his right foot in first, he stepped inside the door. Inside thirty-nine believing souls were seated. Muhammad saw when he looked that twenty-two of them were men and seventeen were women. A voice came from the hidden realm saying, "Muhammad the Prophet has come."

The believers stood up in order to let Muhammad come in. They all showed him a place for him to sit. Hz. 'Ali was also there. Hz. Muhammad sat next to Hz. 'Ali, but he did not recognize that he was Hz. 'Ali. Some questions came to Hz. Muhammad's mind: "Who are they? Are they all on the same level?" He thought to himself, "Who are the greatest among them and who are the least?" He recognized that these questions were not necessary, but he could not help but ask.

"Who are you? What do they call you?" he asked. Those inside replied, "We are the Forty."

Hz. Muhammad said, "Well, I cannot understand who among you is greater and who is lesser."

The Forty replied, "Our greatest is great. Our least is also great. The Forty of us are one and each one of us is the Forty."

Hz. Muhammad asked, "One of you is missing. What happened to that one?"

The Forty said, "That one of us is Selman. He left for the provinces. He went to Iran. But why do you ask? Selman is also here. We consider him to be among us."
Hz. Muhammad wanted the Forty to demonstrate this, so Hz. 'Ali extended his blessed hand. One of the forty, saying "By your leave," struck 'Ali's arm with a knife. Blood began to flow from Hz. 'Ali's arm. At the same time, blood flowed from the wrists of all the forty. At that same moment, a drop of blood came in through the window and fell amid them. This blood was blood from the arm of Selman, who was out in the provinces. Later one of the Forty bandaged Hz. 'Ali's arm. The blood of all the other Forty stopped flowing.

At that time they saw Selman Farsi coming from Iran. Selman brought one single grape. The Forty took this grape and placed it in front of Hz. Muhammad.

They said, "O servant of the poor, perform a service and divide this grape among us."

Hz. Muhammad looked at the situation and thought, "There are forty people and there is only one grape. How can I divide this grape among them?"

At that moment God commanded (the angel) Cebrail saying, "My dear one (Muhammad) is in difficulty. Go quickly, take a platter of light from heaven and deliver it to him. Let him crush the grape inside the platter and make şerbet and give  it to the Forty to drink."

Cebrail took a platter made of light (nur) and came in front of the Messenger of God. Bringing greetings from God, he placed the platter in front of Muhammad. He said, "O Muhammad, turn it into şerbet."

Meanwhile the Forty were watching to see what Muhammad would do with the grape. Suddenly they saw the platter of light appear in front of Hz. Muhammad. The platter shone like the sun. Muhammad placed a drop of water in the platter. Then with his finger he crushed the single grape inside the platter of light and made şerbet. He placed the platter in front of the Forty.

The Forty drank from the şerbet. All of them became as drunk as they were on the Day of Alast when they were first created. They all stood up where they were seated. Saying at once "Ya Allah!" they joined hands with one another. Naked (uryan  buryan), they entered  into semah (mystical  dance) with each other.
Muhammad also entered into semah with them. The Forty's semah continued, 
bathed  in  a  holy  light.  While doing  semah, Hz. Muhammad's blessed turban
(imame) fell from his head. His turban divided into forty pieces. Each one of the Forty took one piece. They made a robe of each piece and put it on.

Hz. Muhammad asked them, "Who are the pirs and the leaders (rehberler)?"
The Forty said, "Our Pir is Shah-i Merdan (the King of the Heroes) 'Ali, with­ out doubt and without debate, and our guide is Cebrail, peace be upon them (alleyhissalem)."

At that moment Hz. Muhammad realized that Hz. Ali was there. Hz. 'Ali walked straight towards Hz. Muhammad. When Hz. Muhammad saw Hz. Ali coming, he bowed down with respect and affection, and invited Hz. Ali to sit next to him. The Forty also joined Muhammad in bowing in respect in front of Hz. 'Ali, opening the way and showing him a place. At that time Hz. Muhammad saw his ring upon the finger of Hz. 'Ali.

For the complete essay When the Prophet Went on the Miraç He Saw a Lion on the Road, by Dr. Vernon Schubel, including an analysis of the text, see The Prophet's Ascension: Cross-Cultural Encounters with the Islamic Mi'raj Tales, published by Indiana University Press. This excerpt is used with the permission of Indiana University Press.