The 283rd prohibition is that a judge is forbidden to rely on the opinion of another judge — either to convict or to acquit — without investigating the case independently and formulating his own opinion and analysis based upon principles of law.

The source of this prohibition is G‑d's statement,1 "Do not speak up in a trial lintos."2 This means that in a trial, one should not merely choose an opinion to follow — e.g. that of the majority or of the higher judges — refraining from offering your own opinion in that case.

In the words of the Mechilta:3 "The verse 'Do not speak up in a trial lintos' teaches that when the votes are cast, you should not say to yourself, 'it's good enough to say the same as Rabbi so-and-so.' Rather, you should give your own opinion. One might think that the same law governs financial cases. The Torah therefore adds, 'A case must be decided based on majority rule.' "

From this prohibition it is also derived that after giving a vote of acquittal, a judge may not change his opinion to one of guilt. This is also conveyed by G‑d's statement (exalted be He), "Do not speak up in a trial lintos," i.e. your speech should not turn him towards conviction.

So too, from this verse it is derived that "capital cases may not be opened by the prosecution, as it is written, 'Do not speak up in a trial lintos'"; that a case may be reopened for acquittal [after conviction], but not for conviction [after acquittal]; and that [when the judges declare their verdict] they should not start from the eldest judge. All these laws are derived from the verse, "Do not speak up in a trial lintos," as explained in the 4th chapter of tractate Sanhedrin, where the details of this mitzvah are given.