What are the connotations of "Vedarshu ha'Shoftim Heiteiv"?
Refe to 13:15:1:1 and notes.
Who is the Beis-Din cross-examining?
Rashi: They are cross-examining the second pair of witnesses who are coming to render the first pair Eidim Zom'min.
To whom is "Eid Sheker" referring?
Rashi: It refers to the first two witnesses. 1
Why does the Torah insert the (otherwise superfluous) word "Eid Sheker ha'Eid"?
Rashi (in Pesachim, 122a): To teach us that any testimony that is not subject to Hazamah is not considered testimony. 1
If "Eid Sheker" is in the singular because it refers to 'Eidus', why does the Torah then write "Va'asisem Lo La'asos le'Achiv" (singular)?
Oznayim la'Torah (on Pasuk 16): Because it indicates that the Eidim Zom'min are one Eidus and that consequently, all of them must become Zom'min in order to be Chayav; otherwise, they are all Patur.
Since the Torah refers to the Eidim as "Eid", it stands to reason that the Torah continues in the singular.
Why does the Torah believe the testimony of the latter pair of witnesses against that of the first pair, irrespective of how many witnesses comprise the Eidim Zom'min?
Ramban: Because traditionally, the Pasuk is speaking in a case where the second pair of witnesses testify that the first pair were with them in a location from where they could not possibly have seen the event on which they testified. Consequently, they are believed, because the latter are testifying about their bodies, which they (the Eidim Zom'min) cannot counter without proof, any more than they could if the witnesses had testified that they murdered or transgressed Shabbos 1 .
B'chor Shor (according to one opinion in Sanhedrin 27a): Believing the second witnesses is a Chidush (a Gezeiras ha'Kasuv), which the Torah instituted in order to frighten people from testifying falsely. 2
Why do we not suspect that the person on whom the Eidim Zomemin testified is a T'reifah, in which case they will not be Chayav Misah?
Chulin, 11b: This teaches us the principle 'Holchin achar ha'Rov' ? that we go after the majority, since most people are not T'reifos.
Why does the Torah add the (otherwise superfluous) phrase "Sheker Anah be'Achiv"?
Seforno: To teach us that the witnesses can only become Zom'min if they lied deliberately, but not if they erred about the time of day because it was a cloudy day, or about the date because they made a mistake as to which day was Rosh Chodesh.