Brother's Keeper?

(5) How does the court intimidate the witnesses in giving testimony for cases of capital law? . . . The court tells them: . . . In cases of capital law, if one testifies falsely, the blood of the accused and the blood of his offspring that he did not merit to produce are ascribed to the witness’s testimony until eternity. The proof for this is as we found with Cain, who killed his brother, as it is stated concerning him: “The voice of your brother’s blood [demei] cries out to Me from the ground” (Genesis 4:10). The verse does not state: Your brother’s blood [dam], in the singular, but rather: “Your brother’s blood [demei],” in the plural. This serves to teach that the loss of both his brother’s blood and the blood of his brother’s offspring are ascribed to Cain. . . . The court tells the witnesses: Therefore, Adam the first man was created alone, to teach you that with regard to anyone who destroys one soul from the Jewish people, i.e., kills one Jew, the verse ascribes him blame as if he destroyed an entire world, as Adam was one person, from whom the population of an entire world came forth. And conversely, anyone who sustains one soul from the Jewish people, the verse ascribes him credit as if he sustained an entire world. The mishna cites another reason Adam the first man was created alone: And this was done due to the importance of maintaining peace among people, so that one person will not say to another: My father, i.e., progenitor, is greater than your father. And it was also so that the heretics who believe in multiple gods will not say: There are many authorities in Heaven, and each created a different person. And this serves to tell of the greatness of the Holy One, Blessed be He, as when a person stamps several coins with one seal, they are all similar to each other. But the supreme King of kings, the Holy One, Blessed be He, stamped all people with the seal of Adam the first man, as all of them are his offspring, and not one of them is similar to another. Therefore, since all humanity descends from one person, each and every person is obligated to say: The world was created for me, as one person can be the source of all humanity, and recognize the significance of his actions. The court says to the witnesses: And perhaps you will say: Why would we want this trouble? Perhaps it would be better not to testify at all. But be aware, as is it not already stated: “And he being a witness, whether he has seen or known, if he does not utter it, then he shall bear his iniquity” (Leviticus 5:1)? It is a transgression not to testify when one can do so. And perhaps you will say: Why would we want to be responsible for the blood of this person? But be aware, as is it not already stated: “When the wicked perish, there is song” (Proverbs 11:10)?