(Mishnah): (Even a small) Sanhedrin sat in a semi-circle, in order that they see each other.

Two scribes stand in front of them - one to the right and one to the left, and they write the words of the Mezakim and the words of the Mechayvim.

R. Yehudah says, there are three. One writes the words of the Mezakim, one writes the words of the Mechayvim, and one writes the words of the Mezakim and the words of the Mechayvim.

Three rows of Chachamim sit in front of the Sanhedrin. Everyone knows his proper place;

If they must give Semichah to one (e.g. one of the Sanhedrin died), they are Somech someone in the first row. Someone from the second row goes to the first row, someone from the third row goes to the second, and they choose someone from the congregation and seat him in the last row;

He does not sit in the [vacated] place of the first [who was promoted], rather, in the place proper for him.

(Gemara - R. Ba bar Yosa citing R. Yochanan): It says here Edah ("v'Shaftu ha'Edah v'Hitzilu ha'Edah"), and it says there Edah (regarding the 10 evil Meraglim. Also here, each Edah is 10; we need another two, to enable convicting through a majority of two over the Edah that is Mezakeh. Beis Din always has an odd number, so there are 23 judges in all.)

A Mishnah (Avos 4:15) teaches "you should be a tail to lions [and not a head of foxes]." Rav brought this also from our Mishnah, which teaches "if they must give Semichah to one, they are Somech from the first [row. This is opposite to] a parable [that commoners say] 'you should be a head of foxes.'

(Mishnah): How do we frighten [the witnesses] in capital cases? We bring them in and threaten them 'perhaps you will say through estimation, or what you heard from other witnesses, [or] you heard from a trustworthy person';

Or, perhaps you don't know that in the end, we will check you with Drishos and Chakiros?

You should know that capital cases are not like monetary cases. In monetary cases (if one testified falsely), he could pay and atone for his sin. In capital cases [if one improperly caused someone to die, he is responsible for the victim's blood, and the blood of all the descendants [that would have come from him] until the end of generations!

So we find regarding Kayin. When he killed Hevel, it says about him "Kol Demei Achicha Tzo'akim Elai Min ha'Adamah" - it does not say 'your brother's blood (singular), rather, Demei - his blood and blood of his descendants (that would have come from him).

Also, it says Demei because his blood was spilled over wood and stones (because Kayin did not know where to strike him to kill him).

Therefore, one man was created in the world, to teach that anyone who kills one Nefesh, it is considered as if he destroyed an entire world, and anyone who saves one Nefesh, it is considered as if he saved an entire world.

Also, this promotes Shalom among people, lest one say to his friend 'my progenitor was created before yours.'

Also, it is lest Minim say that there are many powers in Shamayim (each created a different person).

Also, this shows the greatness of the King of kings, Ha'Kadosh Baruch Hu. If a person makes many coins through one stamp, they all look the same;

And the King of kings, Ha'Kadosh Baruch Hu, made every person in the mold of Adam ha'Rishon, yet no one looks like another person.

Therefore, everyone is obligated to say 'the world was created for me.'

Perhaps you (the witnesses) will say 'why do we need this affliction [to testify to kill the defendant]' - it says "v'Hu Ed Oh Ra'ah Oh Yada Im Lo Yagid..." (if you saw, and do not testify, you bear sin).

Perhaps you will say 'why should we be liable for his blood?' It already says "uva'Avod Resha'im Rinah" (it is good that the wicked die).

(Gemara): What is the case of through estimation? Do not say "we saw him chase him with a sword in his hand. He entered a ruin after him, we entered after him, and we found [the chasd person] dead, and we saw [the Rodef] leave, and the sword was dripping with blood";

Shimon ben Shetach: I should [not] see the consolation [of Tziyon] if I did not see one chasing a man. He entered a ruin; I entered after him. I found [the Nirdaf] dead, and [the Rodef] leave, and a sword dripping with blood;

I said to him "I should see consolation [if it is not true] that you killed him, but what can I do? Your blood is not handed over to me [to testify to execute you]! However, the One who knows thoughts will pay up from that man." [The Rodef] did not finish leaving there before a snake bit him, and he died.