הלכות עדות

When a person delivered false testimony and witnesses testify to that fact, he is called an eid zomeim, "a conspiring witness."
It is a positive mitzvah to requite him in the manner in which he desired through his testimony to effect his colleague. If witnesses testify with regard to a transgression for which one is liable to be stoned to death and it is proved that they testified falsely, they are all stoned. If the transgression was punishable by being burned to death, they are burned to death. Similar laws apply with regard to other forms of capital punishment.
If they testified falsely with regard to a transgression punishable by lashes, each one of them is lashed as are all those obligated to be lashed. We estimate their capacity to bear the lashes and they are lashed. If they testified falsely to obligate the defendant to make a financial payment, we divide that amount according to the number of lying witnesses. Each witness must pay his share. The lying witnesses do not receive lashes when they are required to make financial reimbursement.

When does the above apply? When the witnesses were disqualified through hazamah? When, however, the testimony of two pairs of witnesses contradict each other, both testimonies are of no consequence, but neither of them receives punishment, because we do not know which pair is lying.
What is the difference between testimony which is contradicted and testimony which is disqualified through hazamah? A contradiction concerns the testimony itself. One pair states: "This is what took place," and the other pair states: "It never took place," or that conclusion was obvious from his statements. Hazamah, by contrast, focuses on the witnesses themselves. The witnesses who disqualify them do not know whether the event happened or not.
What is implied? Witnesses come and say: "We saw so-and-so kill a person..." or "...lend money to so-and-so on this-and-this date in this-and-this place." After they testified and the testimony was investigated, two other witnesses came and said: "On that day, we were with you and with those people the entire day and those things never happened. He never killed him," or "...He never lent him." This is considered a contradiction.
Similarly, if witnesses say: "How can you testify in this manner. Either the murderer - or the victim or the borrower or the lender - were with us on that day in another city," the testimony is considered to be contradicted. This is as if they said: "So-and-so did not kill him..." or "So-and-so did not lend him, for they were together with us and this thing did not happen." Similar principles apply in all analogous situations.
If, however, the second pair of witnesses say: "We do not know if so-and-so killed so-and-so on this day in Jerusalem as you say or not. We are, however, testifying that you yourselves were with us in Babylon on that date," the first pair of witnesses are considered as zomeimim and they are executed or required to make financial restitution. The rationale is that the witnesses who disqualified them did not concern themselves with the testimony itself whether it was true or false, but with the presence of the witnesses in the place mentioned.

The fact that the Torah accepted the word of the latter pair of witnesses instead of that of the first pair of witnesses is a Scriptural decree. Even if there were 100 in the first group of witnesses and two witnesses came and disqualified them all through hazamah, saying: "We testify that all 100 of you were together with us on this date in this place," the 100 witnesses are punished on the basis of their testimony. For two witnesses are equivalent to 100 and 100 are equivalent to two. Similarly, when two groups of witnesses contradict each other, we do not follow the majority instead, we nullify the testimony of both.

There is no need for lying witnesses to be given a warning.
When the testimony of witnesses was first contradicted and ultimately, disqualified through hazamah, the lying witnesses are executed, lashed, or forced to make financial restitution. The rationale is that a contradiction is the first stage of hazamah. It is not, however, completed.

The testimony of witnesses can be disqualified through hazamah only in their presence. It can, however, be contradicted outside their presence.
When the testimony of witnesses has been disqualified through hazamah outside the presence of the witnesses, it is considered to have been contradicted. Therefore if the witnesses who have been disqualified through hazamah die before the testimony disqualifying them is delivered in their presence, their testimony is nullified, for the two testimonies contradicted each other.

When the testimony of witnesses in cases of capital punishment was contradicted, but was not disqualified through hazamah, they do not receive lashes. This is true, even if the person they testified was killed comes himself to court to prove the suspected murderer's innocence. The rationale is that the prohibition is punishable by execution. Hence, lashes are not given because of it. Nevertheless, the court has the witnesses beaten with stripes for rebellious conduct according to their perception of the severity of the matter.

A public announcement must be made with regard to lying witnesses. What type of announcement is made? A proclamation is written and sent throughout every city: "So-and-so and so-and-so testified in this manner. They were disqualified through hazamah and executed," "...lashed in our presence," or "fined so-and-so many dinarim." The necessity for this is derived from Deuteronomy 19:20: "Those who remain shall hear and become fearful."

The obligation of lying witnesses to make financial restitution when required is considered as a fine. Therefore, they are not required to pay when they admit their own guilt.
What is implied? The witnesses delivered testimony and their testimony was investigated by the court. Afterwards, they both admitted: "We delivered false testimony. This person does not owe the other person anything." Or they said: "We gave testimony concerning so-and-so with regard to this-and-this amount and we were disqualified through hazamah." They are not required to make restitution because of their own statements.
If, however, they said: "We gave testimony concerning so-and-so, we were disqualified through hazamah in the court of so-and-so and we were obligated to give him this-and-this amount," they are required to make financial restitution. For this is an admission of debt with regard to money that they were already sentenced to pay.
If one witness makes such statements, he is obligated to pay his portion.