Our rabbis taught: A certain student came before Rabbi Joshua and asked him: Is the evening prayer mandatory or optional?
He replied: It is optional.
He then presented himself before Rabban Gamliel and asked him: Is the evening prayer mandatory or optional?
He replied: It is mandatory.
But he said: Didn’t Rabbi Joshua tell me that it is optional?
He said: Wait till the great scholars enter the Study Hall.
When the great scholars came in, the questioner rose and asked: Is the evening prayer mandatory or optional? Rabban Gamliel replied: It is mandatory. Rabban Gamliel said to the rabbis: Is there anyone who disputes this? Rabbi Joshua replied to him: No. He said to him: Did they not report you to me as saying that it is optional? He then went on: Joshua, stand up and let them testify against you! Rabbi Joshua stood up and said: If I were alive and he [the witness] dead, the living could contradict the dead. But since he is alive and I am alive, how can the living contradict the living?
Rabban Gamliel remained sitting and teaching and Rabbi Joshua remained standing, until all the people there began to shout and say to Huzpit the interpreter: “Stop!” and he stopped.
They then said: How long is he [Rabban Gamliel] to go on insulting him [Rabbi Joshua]? ... Come, let us depose him! Whom shall we appoint instead? ...Let us then appoint Rabbi Elazar ben Azariah, who is wise and rich and the tenth in descent from Ezra. He is wise, so that if anyone asks him a question he will be able to answer it. He is rich, so that if occasion arises for paying court to Caesar he will be able to do so. He is tenth in descent from Ezra, so that he has ancestral merit and he [Rabban Gamliel] cannot bring a curse on him. They went and said to him: Will your honor consent to become head of the Academy? He replied: I will go and consult the members of my family. He went and consulted his wife. She said to him: Perhaps they will depose you later on. He replied to her: Let a man use a cup of honor for one day even if it will be broken the next day. She said to him: You have no white hair. He was eighteen years old that day, and a miracle was performed for him and eighteen rows of hair turned white. That is why Rabbi Elazar ben Azariah said: Behold I am like a man of seventy years old, and he did not just say seventy years old. A Tanna taught: On that day the doorkeeper was removed and permission was given to the students to enter. For Rabban Gamliel had decreed: No student who is not the same on the inside as he is on the outside may enter the Study Hall. On that day many stools were added. Rabbi Yohanan said: There is a difference of opinion on this matter between Abba Joseph ben Dostai and the Rabbis: one says that four hundred stools were added, and the other says seven hundred.