Halacha

הלכה א
הַגְּזֵלָה שֶׁלֹּא נִשְׁתַּנֵּית אֶלָּא הֲרֵי הִיא כְּמוֹ שֶׁהָיְתָה אַף עַל פִּי שֶׁנִּתְיָאֲשׁוּ הַבְּעָלִים מִמֶּנָּה וְאַף עַל פִּי שֶׁמֵּת הַגַּזְלָן וַהֲרֵי הִיא בְּיַד בָּנָיו הֲרֵי זוֹ חוֹזֶרֶת לִבְעָלֶיהָ בְּעַצְמָהּ. וְאִם נִשְׁתַּנֵּית בְּיַד הַגַּזְלָן אַף עַל פִּי שֶׁעֲדַיִן לֹא נִתְיָאֲשׁוּ הַבְּעָלִים מִמֶּנָּה קְנָאָהּ בְּשִׁנּוּי וּמְשַׁלֵּם דָּמֶיהָ כִּשְׁעַת הַגְּזֵלָה:
כסף משנה
1.
When an object taken by robbery remains unchanged, it itself must be returned to its original owner. This applies even when the owner has despaired of its return, and even when the robber himself has died, and the article is in his children's possession.
If, however, the article underwent a change while in the robber's possession the robber acquires it because of the change and is required to pay its value at the time of the robbery. This applies even when the owners have not despaired of its recovery.

הלכה ב
וְדִין זֶה דִּין תּוֹרָה הוּא שֶׁנֶּאֱמַר (ויקרא ה כג) "וְהֵשִׁיב אֶת הַגְּזֵלָה אֲשֶׁר גָּזָל". מִפִּי הַשְּׁמוּעָה לָמְדוּ אִם הִיא כְּשֶׁגְּזָלָהּ מְשַׁלֵּם אוֹתָהּ וְאִם נִשְׁתַּנֵּית בְּיָדוֹ מְשַׁלֵּם דָּמֶיהָ. נִתְיָאֲשׁוּ הַבְּעָלִים מִמֶּנָּה וְלֹא נִשְׁתַּנֵּית קָנָה הַגַּזְלָן כָּל הַשֶּׁבַח שֶׁהִשְׁבִּיחָה אַחַר יֵאוּשׁ וְאֵינוֹ מְשַׁלֵּם אֶלָּא כִּשְׁעַת הַגְּזֵלָה. וְדָבָר זֶה מִדִּבְרֵיהֶם מִפְּנֵי תַּקָּנַת הַשָּׁבִים. וּכְשֶׁמַּחְזִיר לוֹ הַגְּזֵלָה שָׁמִין לוֹ הַשֶּׁבַח וְנוֹטֵל מִן הַנִּגְזָל:
כסף משנה
2.
This is the law as prescribed by the Torah, as Leviticus 5:23 states: "And he shall return the object he obtained by robbery." The Oral Tradition interprets that verse to mean: If the object is still as it was at the time of the robbery, it should be returned. If it has undergone a change, he should pay its value.
If the owner despaired of its return, but it did not undergo a change, the robber acquires the right to its increase in value from the time the owner despaired. He is required to pay only the value of the article at the time of the robbery. This is also a Rabbinic ordinance to encourage repentance.
In such an instance, when he returns the object he obtained by robbery, the increase in value is evaluated, and the robber is paid for it by the person he robbed.

הלכה ג
מְכָרָהּ הַגַּזְלָן אוֹ נְתָנָהּ בְּמַתָּנָה אַף עַל פִּי שֶׁלֹּא נִשְׁתַּנֵּית הַגְּזֵלָה אֵינָהּ חוֹזֶרֶת בְּעַצְמָהּ מִיַּד הַלּוֹקֵחַ הוֹאִיל וְנִתְיָאֲשׁוּ הַבְּעָלִים בֵּין לִפְנֵי מְכִירָה וּנְתִינָה בֵּין לְאַחַר מְכִירָה וּנְתִינָה קְנָאָהּ הַלּוֹקֵחַ בְּיֵאוּשׁ וְשִׁנּוּי רְשׁוּת:
כסף משנה
3.
If the robber sold the article obtained by robbery or gave it as a present and the owner despaired of its return, the purchaser is not required to return the article itself even though it did not undergo a change. Since the owner despaired of its return - regardless of whether that took place before the sale or afterwards - the purchaser acquires possession of it, because of the despair and because of the transfer from one domain to another.

הלכה ד
הַגּוֹזֵל וְהִשְׁבִּיחַ וּמָכַר אוֹ הוֹרִישׁ לִפְנֵי יֵאוּשׁ מַה שֶּׁהִשְׁבִּיחַ הוֹרִישׁ וּמַה שֶּׁהִשְׁבִּיחַ מָכַר וְקָנָה לוֹקֵחַ אוֹ יוֹרֵשׁ אֶת הַשֶּׁבַח. וְנוֹטֵל דְּמֵי הַשֶּׁבַח מִן הַנִּגְזָל וּמַחֲזִיר לוֹ הַגְּזֵלָה. וְחוֹזֵר הַנִּגְזָל וְנוֹטֵל דְּמֵי הַשֶּׁבַח מִן הַגַּזְלָן שֶׁהֲרֵי לֹא נִתְיָאֵשׁ. וְכֵן אִם הִשְׁבִּיחַ הַלּוֹקֵחַ אוֹ הַיּוֹרֵשׁ נוֹטֵל הַשֶּׁבַח מִן הַנִּגְזָל:
כסף משנה
4.
When a person obtains an article by robbery, causes it to increase in value, and then sells it or bequeaths it to another person, he bequeaths or sells the increase in value, and the purchaser or the heir acquires the right to this increase. Therefore, at the time of judgment, he should be reimbursed by the original owner for the increase in value, and then return to him the article obtained by robbery. The original owner may then collect the worth of the increase in value from the robber, for he did not despair of its return.
Similarly, if the purchaser or the heir caused the object to increase in value, the original owner should reimburse them for that increase.

הלכה ה
מָכַר הַגַּזְלָן לְעַכּוּ''ם אַף עַל פִּי שֶׁהִשְׁבִּיחַ הָעַכּוּ''ם חוֹזֶרֶת לִבְעָלֶיהָ. מְכָרָהּ הָעַכּוּ''ם לְיִשְׂרָאֵל אַחַר שֶׁהִשְׁבִּיחַ הוֹאִיל וְהַגַּזְלָן יִשְׂרָאֵל וְזֶה שֶׁהִיא בְּיָדוֹ יִשְׂרָאֵל קָנָה הַשֶּׁבַח. וְאִם תָּפַשׂ הַנִּגְזָל אֵין מוֹצִיאִין מִיָּדוֹ:
כסף משנה
5.
If the robber sold the object obtained by robbery to a gentile, and the gentile caused it to increase in value, at the time of judgment, the article and the increase must be returned to the original owner.
If the gentile sold it to a Jew after it increased in value, since the robber is a Jew and the person in possession of the article is a Jew, the purchaser is considered to have acquired the increase in value. If, however, the original owner seizes the increase in value without paying for it, it is not expropriated from his possession.

הלכה ו
כְּבָר בֵּאַרְנוּ שֶׁהַגְּזֵלָה שֶׁהִשְׁבִּיחָה אַחַר יֵאוּשׁ אוֹ אַחַר שֶׁנִּשְׁתַּנֵּית הַשֶּׁבַח לַגַּזְלָן מִפְּנֵי תַּקָּנַת הַשָּׁבִים אַף עַל פִּי שֶׁהִשְׁבִּיחָה מֵאֵלֶיהָ. כֵּיצַד. גָּזַל פָּרָה וְנִתְעַבְּרָה אֶצְלוֹ בֵּין שֶׁיָּלְדָה קֹדֶם שֶׁתְּבָעוֹ בְּדִין בֵּין שֶׁעֲדַיִן לֹא יָלְדָה. גָּזַל רָחֵל וְנִטְעֲנָה אֶצְלוֹ בֵּין שֶׁגְּזָזָהּ קֹדֶם שֶׁתְּבָעוֹ בַּדִּין בֵּין שֶׁעֲדַיִן לֹא גְּזָזָהּ. הוֹאִיל וְנִתְיָאֲשׁוּ הַבְּעָלִים מְשַׁלֵּם כִּשְׁעַת הַגְּזֵלָה. וְאִם יָלְדָה וּגְזָזָהּ הַגִּזּוֹת וְהַוְּלָדוֹת שֶׁל גַּזְלָן. וְאִם עֲדַיִן לֹא יָלְדָה וְלֹא גְּזָזָהּ שָׁמִין לוֹ וְנוֹטֵל הַשֶּׁבַח מִן הַנִּגְזָל וּמַחֲזִיר הַבְּהֵמָה עַצְמָהּ:
כסף משנה
6.
As explained, in order to encourage repentance our Sages ruled that when an article obtained by robbery increases in value after the owner despairs of its return or after it has undergone a change, the robber is entitled to the increase in value. This applies even when the change comes about as a matter of course.
What is implied? If a person obtained a cow by robbery and it became pregnant in his possession, whether or not it bore a calf before he was called to court because of the robbery - since the owner despaired of its return, he is required to pay only the value of the cow at the time of the robbery. Similarly, if he stole a sheep and it grew wool, whether he sheared it before he was called to court or it had not yet been shorn, he is required to pay only its value at the time of the robbery.
If it bore offspring or was shorn, the robber is entitled to the offspring or the shearings. If it had not borne offspring, nor was it shorn at that time, the animal's increase in value is evaluated and may be collected from the original owner. Then the animal itself is returned.

הלכה ז
גָּזַל פָּרָה מְעֻבֶּרֶת וְנִתְיָאֲשׁוּ הַבְּעָלִים וְאַחַר כָּךְ יָלְדָה. רָחֵל טְעוּנָה וְנִתְיָאֲשׁוּ הַבְּעָלִים וְאַחַר כָּךְ גְּזָזָהּ. מְשַׁלֵּם דְּמֵי פָּרָה הָעוֹמֶדֶת לֵילֵד וּדְמֵי רָחֵל הָעוֹמֶדֶת לִגָּזֵז. וְאִם לִפְנֵי יֵאוּשׁ אוֹ קֹדֶם שֶׁנִּשְׁתַּנָּה יָלְדָה אוֹ גְּזָזָהּ הֲרֵי הַגִּזּוֹת וְהַוְּלָדוֹת שֶׁל בְּעָלִים. וְאַף עַל פִּי שֶׁנִּתְעַבְּרָה אוֹ נִטְעֲנָה בְּיַד הַגַּזְלָן הוֹאִיל וְלֹא נִתְיָאֲשׁוּ הַבְּעָלִים וְלֹא נִשְׁתַּנֵּית הַגְּזֵלָה. בִּרְשׁוּת בְּעָלֶיהָ הִיא עֲדַיִן אַף עַל פִּי שֶׁהַגַּזְלָן חַיָּב בָּאֳנָסֶיהָ:
כסף משנה
7.
If a person obtained a pregnant cow by robbery, the owner despaired of its return and then it bore offspring, or he obtained a sheep laden with wool by robbery, the owner despaired of its return and then it was shorn, the robber should pay the value of a cow ready to bear offspring and a sheep ready to be shorn.
If the animal bore offspring or was shorn before the owner despaired of its return, the shearings or the offspring belong to the original owner. This applies even if the animal became pregnant or grew wool while in the possession of the thief. Since the owner did not despair, and the animal did not undergo a change, the object obtained by robbery is still considered to belong to its original owner, although the robber is held responsible in cases of loss due to forces beyond his control.

הלכה ח
גָּנַב אוֹ גָּזַל וְהִקְדִּישׁ וְטָבַח אַחַר שֶׁנִּתְיָאֲשׁוּ הַבְּעָלִים הֲרֵי הִיא בִּרְשׁוּת הַגַּזְלָן מִשָּׁעָה שֶׁהִקְדִּישָׁהּ בִּלְבַד כְּדֵי שֶׁלֹּא יְהֵא חוֹטֵא נִשְׂכָּר. וְכָל וַלְדוֹתֶיהָ וְגִזּוֹתֶיהָ מִשְּׁעַת גְּנֵבָה עַד שְׁעַת הֶקְדֵּשׁ שֶׁל בְּעָלִים:
כסף משנה
8.
If a person stole or obtained an animal by robbery and consecrated or slaughtered it after its owner despaired of its return, it is considered to be the thief's property only from the time he consecrated it. This was enacted so that the sinner will not profit. All its offspring and its shearings from the time that it was stolen until the time it was consecrated belong to its original owner.

הלכה ט
בַּמֶּה דְּבָרִים אֲמוּרִים בְּשֶׁבַח הַבָּא מֵאֵלָיו כְּגוֹן גִּזּוֹת וּוְלָדוֹת. אֲבָל אִם הָיְתָה כְּחוּשָׁה וּפִטְּמָהּ אֲפִלּוּ לִפְנֵי יֵאוּשׁ נוֹטֵל מִן הַנִּגְזָל שְׁבַח הַפִּטּוּם. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה מִשֶּׁבַח שֶׁיֵּשׁ בּוֹ הוֹצָאָה:
כסף משנה
9.
When does the above apply? To an increase in value that comes as a matter of course - e.g., an animal's shearing or its offspring. If, however, an animal was gaunt, and the robber fattened it, the robber may collect the increase in value due to the fattening from the original owner, even if it took place before the owner despaired. The same applies with regard to all instances where the increase in value comes about as a result of expense.

הלכה י
שִׁנּוּי הַחוֹזֵר לִבְרִיָּתוֹ אֵינוֹ שִׁנּוּי. כֵּיצַד. הַגּוֹזֵל עֵצִים וְדִבְּקָן בְּמַסְמְרִים וְעָשָׂה מֵהֶן תֵּבָה אֵינוֹ שִׁנּוּי שֶׁהֲרֵי אֶפְשָׁר לְפָרְקָן וְחוֹזְרִין לוּחוֹת כְּשֶׁהָיוּ:
כסף משנה
10.
A change that can revert to its original state is not considered to be a change.
What is implied? When a person obtains boards by robbery and attaches them to each other with nails and makes a chest, this is not considered a change. For it is possible to separate them and make them simple boards, as they were previously.

הלכה יא
גָּזַל עָפָר וַעֲשָׂאָהוּ לְבֵנָה לֹא קָנָה שֶׁאִם יָדֹק הַלְּבֵנָה תַּחְזֹר עָפָר כְּשֶׁהָיְתָה. גָּזַל לָשׁוֹן שֶׁל מַתֶּכֶת וַעֲשָׂאָהוּ מַטְבֵּעַ לֹא קָנָה שֶׁאִם יַתִּיךְ הַמַּטְבֵּעַ יַחְזֹר לָשׁוֹן כְּשֶׁהָיְתָה. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה:
כסף משנה
11.
If a person obtained sand by robbery and made it into a brick, he does not acquire it, because one can crush the brick and return it to sand.
If he obtained a strip of metal by robbery and made it into a coin, he does not acquire it, because one can melt the coin and return it to a strip of metal, as it was beforehand. The same principles apply in other similar instances.

הלכה יב
אֲבָל הַגּוֹזֵל עֵצִים וּשְׂרָפָן וְקִצְּצָן אוֹ חָקַק בָּהֶן וַעֲשָׂאָן כֵּלִים. אוֹ שֶׁגָּזַל צֶמֶר וּצְבָעוֹ אוֹ נִפְּצוֹ וְלִבְּנוֹ. אוֹ שֶׁגָּזַל טָווּי וְעָשָׂהוּ בֶּגֶד. אוֹ שֶׁגָּזַל לְבֵנָה וַעֲשָׂאָהּ עָפָר אוֹ אֲבָנִים וְסִתְּתָן אוֹ מָעוֹת וְהִתִּיכָן. הֲרֵי זֶה שִׁנּוּי בְּיָדוֹ שֶׁאִם יַעֲשֵׂם מָעוֹת אֲחֵרוֹת פָּנִים חֲדָשׁוֹת הֵן. וְכֵן כָּל כַּיּוֹצֵא בָּהֶן:
כסף משנה
12.
If, however, a person obtained boards by robbery and burned them, cut them or carved them, and in this way fashioned them into a utensil; he obtained wool by robbery and dyed it, spun it or whitened it; he obtained threads by robbery and made them into a garment; he obtained a brick by robbery and made it into dust; obtained stones by robbery and smoothed them; or he obtained coins by robbery and melted them - this is considered a change, for if he makes other coins - or similarly undoes the other changes mentioned above - they are considered to be new entities. The same principles apply in all similar situations.

הלכה יג
הַגּוֹזֵל מָעוֹת יְשָׁנוֹת וְשָׁפָן וְחִדְּשָׁן לֹא קָנָה שֶׁהֲרֵי מִתְיַשְּׁנִין וְחוֹזְרִין כְּשֶׁהָיוּ. גָּזַל מָעוֹת חֲדָשִׁים וְיִשְּׁנָם קָנָה שֶׁאִם יְחַדְּשֵׁם פָּנִים חֲדָשׁוֹת הֵן. גָּזַל דֶּקֶל מְחֻבָּר וְקִצְּצוֹ לֹא קָנָה וַאֲפִלּוּ כְּרָתוֹ חֻלְיוֹת חֻלְיוֹת. עָשָׂהוּ קוֹרוֹת קָנָה:
כסף משנה
13.
When a person robs old coins, polishes them and renews them, he is not considered to have acquired them, for they will age and return to their previous state. If, however, he obtains new coins by robbery and causes them to look old, he does acquire them. For if they were made to appear new again, that would be considered to be a new development.
A person who robs a date palm that is growing and cuts it down does not acquire it. This applies even if he cuts it into sections. If he makes it into boards, he does acquire it.

הלכה יד
גָּזַל קוֹרוֹת גְּדוֹלוֹת וַעֲשָׂאָן קְטַנּוֹת לֹא קָנָה. עֲשָׂאָן לוּחוֹת עַד שֶׁנִּשְׁתַּנָּה שְׁמָם קָנָה. גָּזַל לוּלָב וְהִפְרִיד עָלָיו קָנָה הֶעָלִים. גָּזַל עָלִים וַעֲשָׂאָן חֻפִּיָיה קָנָה. גָּזַל טָלֶה וְנַעֲשָׂה אַיִל עֵגֶל וְנַעֲשָׂה שׁוֹר הֲרֵי זֶה שִׁנּוּי בְּיָדוֹ וְקָנָהוּ וּמְשַׁלֵּם כִּשְׁעַת הַגְּזֵלָה. וְאַף עַל פִּי שֶׁלֹּא נִתְיָאֲשׁוּ הַבְּעָלִים:
כסף משנה
14.
If a person obtains large beams by robbery and cuts them into small beams, he does not acquire them. If he cuts them into boards, causing them to be called by a different name, he does acquire them.
If one obtained a palm branch by robbery and separated its leaves, one acquires the leaves. If one obtained palm leaves by robbery and made them into a broom, one acquires the broom.
If one obtains a lamb by robbery and it becomes a ram, or one obtains a calf by robbery and it becomes an ox, it is considered to have undergone a change while in the robber's possession. Therefore, he is considered to have acquired it, and he is required to pay only the value of the article at the time of the robbery, despite the fact that the owner never despaired of the article's return.

הלכה טו
גָּזַל כְּלִי וּשְׁבָרוֹ אֵין שָׁמִין לוֹ הַפְּחָת אֶלָּא מְשַׁלֵּם דָּמָיו וְהַכְּלִי הַשָּׁבוּר שֶׁל גַּזְלָן. וְאִם רָצוּ הַבְּעָלִים לִטּל הַכְּלִי הַשָּׁבוּר נוֹטְלִין וּמְשַׁלֵּם הַפְּחָת. שֶׁזּוֹ תַּקָּנָה הִיא לַבְּעָלִים וְאִם לֹא רָצוּ הָרְשׁוּת בְּיָדָן. וְכֵן כָּל כַּיּוֹצֵא בָּזֶה:
כסף משנה
15.
If a person obtains a utensil by robbery and breaks it, we do not evaluate its depreciation. Instead, the robber is obligated to pay its worth, and he is given the broken utensil.
If, however, the original owner desires to take the broken utensil, he is granted it, and the robber must pay for its depreciation. This ordinance was instituted for the sake of the owner, and if he does not desire it, he is granted that prerogative. Similar principles apply in other analogous situations.

הלכה טז
גְּזֵלָה שֶׁלֹּא נִשְׁתַּנֵּית וְהוּקְרָה אַף עַל פִּי שֶׁנִּתְיָאֲשׁוּ הַבְּעָלִים מִמֶּנָּה הֲרֵי זוֹ חוֹזֶרֶת לַבְּעָלִים וְאֵין לַגַּזְלָן בָּהּ כְּלוּם. שֶׁלֹּא תִּקְּנוּ לַגַּזְלָן אֶת הַשֶּׁבַח אַחַר יֵאוּשׁ אֶלָּא כְּגוֹן גִּזּוֹת וּוְלָדוֹת. אֲבָל שֶׁבַח הַיֹּקֶר אִם הָיְתָה הַגְּזֵלָה חוֹזֶרֶת בְּעֵינֶיהָ אֵינוֹ זוֹכֶה בָּהּ:
כסף משנה
16.
When an object obtained by robbery does not undergo a change, but its value increases, it itself must be returned to its original owner, and the robber is not entitled to anything. This applies even if the owner has despaired of its return.
For the Sages granted the robber only the increase in value after the owner despaired of the object's return, in instances like the shearing of wool and the offspring. He is not, however, granted any increase in value that comes from the rise in article's worth when it is returned intact to its owner.

נזיקין הלכות גזילה ואבידה פרק ב
Nezikim Gezeilah and Aveidah Chapter 2