הלכות גזילה ואבידה

Whenever a person becomes financially obligated to a fellow Jew, denies that obligation and takes a false oath to support his denial, should he later admit his obligation he is liable to return the principal that he denied plus a surcharge of one fifth of the new total. He is also liable to bring a sacrifice, which is called a guilt offering, for robbery.

The above applies to any of the following: one who robbed, one who withheld money due a colleague, one who stole, one who took a loan, one who was given an entrusted article, one who discovered a lost article and denied it, a partner with whom money belonging to the partnership remained, and an employer for whom a worker performed work, but was not paid.
To state the general principle: Whenever a person who admitted the obligation would be obligated by law to pay, he must pay the principal and a fifth if he denies his obligation, as Leviticus 5:21 says: "If he denies his colleague's claim regarding an entrusted object...."

When does the above apply? When the person is obligated to pay because of his own actions. When, however, he is liable because of his father, he is not liable for the additional fifth.
What is implied? If one's father robbed or stole or was in debt to others, and the son knew of the matter, and after the father's death the son denied the claim, took an oath and afterwards admitted his liability, he need pay only the principal. For Leviticus 5:23 states: "that he obtained by robbery," implying that one is liable for an additional fifth for one's own robbery, but not for robbery committed by one's father.

When does the above apply? When the object obtained by robbery no longer exists. Different laws apply however, when a person's father obtained an object by robbery and then died, and the object still exists. If the heir denies his obligation, takes an oath to that effect and then admits his liability, he is liable for the principal and the addition of a fifth.

A person who takes a false oath in response to the claim of a gentile and later admits his guilt is obligated to pay the principal, but not the additional fifth, for Leviticus 5:21 speaks of one who "denies his colleague's claim."
Similarly, a person who takes less than the worth of a p'rutah by robbery, denies the charge and takes a false oath to that effect is not liable to pay an additional fifth, for anything less than a p'rutah's worth is not considered a significant financial responsibility.
What is meant by an additional fifth? One fourth of the principal. For example, if a person obtained four zuz by robbery and took a false oath, he must pay five. If the object obtained by robbery itself still exists, it must be returned and a fourth of its value added.

A person who takes a false oath denying a financial claim is not liable to pay an additional fifth unless he himself admits his guilt. If, however, witnesses come and despite his continued denial establish his guilt through their testimony, he is liable to pay only the principal, but not the additional fifth.
The rationale is that the additional fifth and the sacrifice were instituted for the sake of atonement. Therefore, he is obligated for them only when it is his admission that makes him liable.

When a person robs from a colleague, even if he denied the robbery - as long as he did not take a false oath - if he afterwards admits his guilt he is not liable to seek out the owner to return the money in his possession. Instead, it may remain in the possession of the robber until the owners come and take his due.
If, however, he took a false oath concerning property worth a p'rutah or more, he is obligated to seek out the owner to return the money to him even if he is on far removed islands. The rationale is that once the robber took a false oath, the owner has despaired of the return of his property and will not demand it again.

Even if a robber returned the entire worth of the object obtained by robbery with the exception of a p'rutah, he is obligated to bring it to the original owner. He may not give the p'rutah to the owner's son or agent unless the owner appointed an agent for this purpose in the presence of witnesses.
If the robber brings the principal and the additional fifth to the Rabbinic court in his city, he may bring a guilt offering and gain atonement thereby. The court will then ensure that the object obtained by robbery will reach its original owner. Similarly, the robber may give the article to an agent of the court. Whenever a person returns an object obtained by robbery or the like to a Rabbinic court, he has fulfilled his obligation to return it.

When the robber gave the original owner the principal, but not the additional fifth, the owner waived payment of the principal but not of the additional fifth, or he waived payment of both with the exception of less than a p'rutah's worth of the principal, the robber does not have to seek out the owner. Instead, when the owner comes he will take the remainder of what is due him.
This ruling is followed when the owner waives payment of everything but less than a p'rutah's worth of the principal even when the object obtained by robbery itself exists. We do not suspect that perhaps the value of the article will increase, and thus the portion remaining will become worth a p'rutah.
If, however, the robber gave the owner the additional fifth, but did not give him the principal, or if the owner waived payment of the additional fifth but not of the principal, or he waived payment of both with the exception of a p'rutah's worth of the principal, the robber must seek out the owner or give the money to the Rabbinic court in his town, as explained in the previous halachot.

If the robber returned the principal to the owner after denying his claim and taking a false oath and then denied owing him the additional fifth and took a false oath concerning this, the additional fifth is considered as part of the principal with regard to all matters, and the robber must pay another fifth because of it.
This is derived from Leviticus 5:24, which states: "And he shall add its fifths." The use of the plural teaches that he must add a fifth to a fifth if he continues to take false oaths until the fifth that he denies - and concerning which he takes a false oath - is worth less than a p'rutah.

The following rule applies with regard to a person who had been entrusted with an object for safekeeping and who repeatedly took false oaths concerning the entrusted article. For example, the watchman claimed that the article was lost, took a false oath to support his claim and then admitted that it was in his possession. He then claimed it was lost and took a second false oath and then admitted it was in his possession. He must pay an additional fifth for every false oath, plus the principal.
This is derived from the phrase cited above: "And he shall add its fifths." The use of the plural teaches that he must pay several fifths for one principal.