Gittin, Chapter Five, Mishnah 6. This mishnah deals with the laws of sikarikon. A 'sikarikon' is the term for gentile land robbers, who would seize land belonging to Jews and afterward sell it, sometimes even to other Jews. The mishnah teaches us three distinct stages in this halachah, how one who buys land from a sikarikon must conduct himself, and we will examine all three.
What is a sikarikon:
The term 'sikarikon' is used both for the land robber himself and as the name of the laws in which we learn how to deal with him. These laws did not actually apply at the very beginning of that period, at the time the lands were seized, and the reason is this: the halachah is that when a robber takes land under threat of death - telling the owner that he will kill him unless he hands over his field - the sale is a valid sale. We say that a person in such circumstances transfers his land completely in order to save his life. Therefore, although this is a wretched situation, one who purchases the land from the sikarikon has made a valid purchase.
This is why the mishnah opens by saying: "Lo hayah sikarikon biYehudah baharugei hamilchamah" - the laws of sikarikon, which we will discuss below, did not apply in Judea during the period when people were being killed in the course of the war, referring to the Roman wars at the end of the Second Temple era. But "meharugei hamilchamah va'eilach - yesh bah sikarikon" - once the killing stopped, and the threats were made in other ways that were not threats of death, the laws of sikarikon took effect. From here on the mishnah describes the various stages of this halachah.
The order of purchase - from the sikarikon or from the owner:
"Lakach misikarikon vechazar velakach mibaal habayis - mikacho batel" - a Jew who bought a field from the sikarikon who seized it, and afterward went and bought it from the householder as well, from the original owner from whom it was taken, since it truly belongs to him and there was no valid sale here - the second purchase is null and void. The reason: we assume that the owner who sells it to him is still acting out of fear of the sikarikon, and it is not his genuine wish to sell. He is merely saying to himself: I will sell it to him now, and I will bring him to a din Torah later and recover my land.
"Mibaal habayis vechazar velakach misikarikon - mikacho kayam" - if he first bought from the householder and only afterward turned to the sikarikon and bought from him as well, the sale is valid. For at the time the householder sold to him, he was under no duress to support or consent to the purchase from the sikarikon, and he did not even necessarily know that the sikarikon was interested in selling to that particular Jew. Only when the purchase from the owner comes after the purchase from the sikarikon is it null and void.
A parallel halachah - land liened for a kesubah:
The mishnah teaches a similar halachah with the same ordering, even though there is no element of duress in it at all: a field that the husband designated for payment of his wife's kesubah, so that the wife has a claim and a lien upon it.
"Lakach min ha'ish vechazar velakach min ha'ishah - mikacho batel" - the buyer bought the land from the husband, to whom it belongs, and afterward approached the wife and said to her: I know that the field I bought from your husband is designated for your kesubah, and I want to buy it from you as well so that I will hold your rights in it too. This is not a valid sale, since the wife can say: "Nachas ruach asisi le'baali" - he wanted to sell to you, so I agreed, but in truth I did not want this.
"Min ha'ishah vechazar velakach min ha'ish - mikacho kayam" - if he first bought from the wife and only afterward from the husband, the purchase is valid, for the wife did not act in order to confirm her husband's sale, since her husband's sale had not yet taken place. And this is the parallel to the case of the sikarikon.
The later enactment - a quarter to the owner:
Everything stated regarding the sikarikon, that only in this order does the purchase take effect - that he first buy from the householder and afterward from the sikarikon, and without this it is not valid - that was the original enactment. However, a later beis din ruled that the buyer from the sikarikon keeps the land, and he does not need to buy it from the householder.
Nevertheless, since the sikarikon received the land for free, for he is a thief and a robber, it is his way to sell it to a Jew at a price below market value. The assumption is that the buyer saved at least a quarter of the price, and since the price came down by a quarter, we say that the one who buys from the sikarikon must give the original owner a quarter of the value - the money he saved.
The Gemara explains that this means a quarter of the land, which is a third of the money. For example, one who buys a field from the sikarikon for three hundred zuz, when its true value is four hundred, gives the owner one hundred zuz, which is a quarter of the true value. And if the original owner wishes, he can say: I do not want cash, give me a quarter of the field itself. This is the meaning of the statement that a quarter in land is a third in money.
And when does this apply, that giving the money suffices? When the owner lacks the means to buy the land from the person who bought it. But if they do have the ability to purchase it, whether from the buyer or even from the sikarikon himself, they take precedence, and they hold the first right of purchase. Only when they do not have the funds does the buyer keep the land, and he must compensate the owner for the discount he received.
Finally the mishnah says that Rabbi convened a beis din, and they voted and concluded: if the field remained in the hands of the sikarikon for twelve months and the original owners did not buy it back, whoever comes first and acquires it has acquired it, and there is no need to wait for the owners. Even so, he must still give that same quarter, that same third of the money, to the owners, because that was the discount he received.
In summary: in this mishnah we learned the three stages of the laws of sikarikon: first, that land taken under threat of death - its sale stands and the law of sikarikon does not apply to it at all; then, once the laws took effect, that only one who buys first from the householder and afterward from the sikarikon has a valid purchase, and likewise in the parallel halachah of land liened for a kesubah; and finally, the enactment of the later beis din that the buyer keeps the land and gives the owner a quarter, and the enactment of Rabbi's beis din that after twelve months whoever comes first acquires it, provided that he gives that same quarter to the owners.