וַעֲשִׂ֣יתֶם ל֔וֹ כַּאֲשֶׁ֥ר זָמַ֖ם לַעֲשׂ֣וֹת לְאָחִ֑יו וּבִֽעַרְתָּ֥ הָרָ֖ע מִקִּרְבֶּֽךָ׃
그가 그 형제에게 행하려고 꾀 한대로 그에게 행하여 너희 중에서 악을 제하라
Mekhilta DeRabbi Yishmael
"Do not place your hand with an evildoer": This was the practice of the "clean-minded men of Jerusalem." They would not go to a feast until they knew who was going with them, and they would not sign a writ of divorce until they knew who was signing with them. R. Nathan says: "Do not place your hand, etc.": Do not make violence a witness — to exclude evildoers and robbers from being witnesses. As it is written (Devarim 19:16) "If a man of violence rise up against another to testify, etc. … (19) then you shall do to him as he schemed to do, etc."
Mekhilta DeRabbi Yishmael
(Ibid.) "You shall not testify against your neighbor false testimony." (Devarim 19:19) "And you shall do to him as he (a scheming witness) schemed to do against his brother, etc." tells us of the punishment. Whence the exhortation? "You shall not testify against your neighbor, etc."