To not redeem the firstborn of a pure animal: That we should not redeem the firstborn of a pure (kosher) animal. Since the Torah had commanded that the firstborn donkey be redeemed, it may have come to our minds to also redeem the firstborn of a pure animal with another animal. Therefore this prevention came to us, that we should never redeem it. And even if one transgressed and redeemed it, it is not redeemed. About this is it stated (Numbers 18:17), “But the firstborn of an ox, the firstborn of a sheep, or the firstborn of a goat should not be redeemed; they are sacred.” The verse elucidated the three types of pure (domesticated) beasts that are subject to the commandment of the firstborn, as the seven varieties of wild animals are not included in the law of firstborns, and as I explained in the Order of Bo (Sefer HaChinukh 17).
I wrote about the roots of the commandment of the firstborn to give it to the priest there. The matter of the warning not to redeem it is connected to it — so take it from there.
From the laws of the commandment: Rambam, may his memory be blessed, wrote (Mishneh Torah, Laws of Firstlings 1:17), “Just as the firstborn cannot be redeemed, so too can the priest not sell it while it is still unblemished. As since it stands to be offered as a sacrifice, the priest does not have the right to sell it. But at this time (when there is no Temple), since it is destined to be eaten, behold, it is permitted to sell it, even though it is unblemished — whether to a priest or an Israelite.” To here [are his words]. Certainly about that which our Teacher, may his memory be blessed, said that it is destined to be eaten, his intention was to say, when it gets a blemish. And a blemished firstborn can be sold by the priest at any time, whether the Temple [is standing] or whether the Temple [is not standing], whether it is alive or whether it is slaughtered, to any person, even a non-Jew, as it is completely non-sacred, as it is written (Deuteronomy 12:15), “The pure and the impure together, like the gazelle and the deer.” Still, the Sages warned not to sell it in the marketplace in public, but rather at home. The rest of its details are elucidated in Tractate Bekhorot [Chapter 5]. (See Tur, Yoreh Deah 306.)
And this commandment is practiced in the Land of Israel, like the commandment of sanctifying the firstborn pure animals, which is only practiced in the Land of Israel, according to some commentators (see Beit Yosef, Yoreh Deah 306) — both when the Temple [is standing] and when the Temple [is not standing] — as it is stated (Deuteronomy 14:23), “And you shall eat before the Lord, Your God, the tithes of your grain, etc. and the firstborn of your cattle and your sheep.” And they, may their memory be blessed, expounded [it to mean] (Temurah 21b), from the place that you bring your tithes — which is the Land of Israel — you shall bring your sheep and cattle. And if one brought a firstborn animal from outside the Land, they would not accept it from him and it may not be sacrificed, as it is completely non-sacred. Everyone is obligated in this commandment, priests, Levites, and Israelites, as it stated (Deuteronomy 15:19), “Any firstborn that is born, etc.” (Mishneh Torah, Laws of Firstlings 1:7). And even though the priests and the Levites are exempt from redeeming the firstborn of man and the one that exits the donkey, as we have written about each one of them in this Order (Sefer HaChinukh 392) and in the Order of Bo el Pharaoh (Sefer HaChinukh 22), they are obligated in this. And one who transgressed this and redeemed his firstborn pure animal — even though his actions were not effective and it is not redeemed, but rather it is sacred as it was [before] — he has violated a negative commandment. As regarding the transgression of the negative commandment, [the efficacy of] the violation of a negative commandment does not concern us, as is found in the first chapter of Temurah (Temurah 4b), in the disagreement of Abbaye and Rava. But he is not lashed, as he could transgress it without an act.
שֶׁלֹּא לִפְדּוֹת בְּכוֹר בְּהֵמָה טְהוֹרָה – שֶׁלֹּא נִפְדֶּה בְּכוֹר בְּהֵמָה טְהוֹרָה, מִפְּנֵי שֶׁהַתּוֹרָה צִוְּתָה לִפְדּוֹת פֶּטֶר חֲמוֹר, אוּלַי יַעֲלֶה עַל דַּעְתֵּנוּ לִפְדּוֹת גַּם כֵּן בְּכוֹר בְּהֵמָה טְהוֹרָה בִּבְהֵמָה אַחֶרֶת עַל כֵּן בָּאַתְנוּ הַמְּנִיעָה בָּזֶה, שֶׁלֹּא נִפְדֶּה אוֹתוֹ לְעוֹלָם. וַאֲפִלּוּ עָבַר וּפָדָהוּ אֵינוֹ פָּדוּי, וְעַל זֶה נֶאֱמַר (במדבר יח יז) אַךְ בְּכוֹר שׁוֹר אוֹ בְכוֹר כֶּשֶׂב אוֹ בְכוֹר עֵז לֹא תִפְדֶּה קֹדֶשׁ הֵם. בֵּאֵר הַכָּתוּב שְׁלֹשׁ הַבְּהֵמוֹת הַטְּהוֹרוֹת, שֶׁהֵן בְּחִיּוּב מִצְוַת בְּכוֹר, כִּי מִינֵי הַחַיָּה שֶׁהֵם שִׁבְעָה, אֵינָם בְּתוֹרַת בְּכוֹרוֹת, וּכְמוֹ שֶׁכָּתַבְתִּי בְּסֵדֶר "בֹּא" (מצוה יח).
To not redeem the firstborn of a pure animal: That we should not redeem the firstborn of a pure (kosher) animal. Since the Torah had commanded that the firstborn donkey be redeemed, it may have come to our minds to also redeem the firstborn of a pure animal with another animal. Therefore this prevention came to us, that we should never redeem it. And even if one transgressed and redeemed it, it is not redeemed. About this is it stated (Numbers 18:17), “But the firstborn of an ox, the firstborn of a sheep, or the firstborn of a goat should not be redeemed; they are sacred.” The verse elucidated the three types of pure (domesticated) beasts that are subject to the commandment of the firstborn, as the seven varieties of wild animals are not included in the law of firstborns, and as I explained in the Order of Bo (Sefer HaChinukh 17).
מִשָּׁרְשֵׁי מִצְוַת הַבְּכוֹר לְתִתּוֹ לַכֹּהֵן, כָּתַבְתִּי שָׁם. וְעִנְיַן הָאַזְהָרָה שֶׁלֹּא לִפְדּוֹתוֹ נִקְשָׁר עִמּוֹ, וְקָחֶנּוּ מִשָּׁם.
I wrote about the roots of the commandment of the firstborn to give it to the priest there. The matter of the warning not to redeem it is connected to it — so take it from there.
מִדִּינֵי הַמִּצְוָה. כָּתַב הָרַמְבַּ"ם זִכְרוֹנוֹ לִבְרָכָה (בכורות א, יז) הַבְּכוֹר כְּמוֹ שֶׁאֵין פּוֹדִין אוֹתוֹ כָּךְ אֵין הַכֹּהֵן יָכוֹל לְמָכְרוֹ בְּעוֹדוֹ תָּם, דְּכֵיוָן שֶׁהוּא עוֹמֵד לְקָרְבָּן אֵין לַכֹּהֵן זְכוּת בּוֹ לְמָכְרוֹ. וּבַזְּמַן הַזֶּה שֶׁאֵין בַּיִת, הוֹאִיל וְלַאֲכִילָה עוֹמֵד הֲרֵי זֶה מֻתָּר לְמָכְרוֹ, וְאַף עַל פִּי שֶׁהוּא תָּמִים, בֵּין לְכֹהֵן, בֵּין לְיִשְׂרָאֵל, עַד כָּאן. וַדַּאי שֶׁזֶּה שֶׁאָמַר רַבֵּנוּ זִכְרוֹנוֹ לִבְרָכָה הוֹאִיל וְלַאֲכִילָה עוֹמֵד כַּוָּנָתוֹ לוֹמַר לִכְשֶׁיִּפֹּל בּוֹ מוּם. וּבְכוֹר בַּעַל מוּם יֵשׁ לַכֹּהֵן לְמָכְרוֹ בְּכָל זְמַן, בֵּין בִּפְנֵי הַבַּיִת וְשֶׁלֹּא בִּפְנֵי הַבַּיִת, בֵּין חַי בֵּין שָׁחוּט, לְכָל אָדָם, וַאֲפִלּוּ לְגוֹי, דִּכְחֻלִּין גְּמוּרִין הוּא. כְּמוֹ שֶׁכָּתוּב (דברים יב טו) הַטָּמֵא וְהַטָּהוֹר יַחְדָּו כַּצְּבִי וְכָאַיָּל. וּמִכָּל מָקוֹם, הִזְהִירוּ חֲכָמִים שֶׁלֹּא לְמָכְרוֹ בַּשּׁוּק דֶּרֶךְ פַּרְהֶסְיָא, אֶלָּא בַּבַּיִת. יֶתֶר פְּרָטֶיהָ, מְבֹאָרִים בְּמַסֶּכֶת בְּכוֹרוֹת (פ"ה) [יו"ד סי' שו].
From the laws of the commandment: Rambam, may his memory be blessed, wrote (Mishneh Torah, Laws of Firstlings 1:17), “Just as the firstborn cannot be redeemed, so too can the priest not sell it while it is still unblemished. As since it stands to be offered as a sacrifice, the priest does not have the right to sell it. But at this time (when there is no Temple), since it is destined to be eaten, behold, it is permitted to sell it, even though it is unblemished — whether to a priest or an Israelite.” To here [are his words]. Certainly about that which our Teacher, may his memory be blessed, said that it is destined to be eaten, his intention was to say, when it gets a blemish. And a blemished firstborn can be sold by the priest at any time, whether the Temple [is standing] or whether the Temple [is not standing], whether it is alive or whether it is slaughtered, to any person, even a non-Jew, as it is completely non-sacred, as it is written (Deuteronomy 12:15), “The pure and the impure together, like the gazelle and the deer.” Still, the Sages warned not to sell it in the marketplace in public, but rather at home. The rest of its details are elucidated in Tractate Bekhorot [Chapter 5]. (See Tur, Yoreh Deah 306.)
וְנוֹהֶגֶת מִצְוָה זוֹ בְּאֶרֶץ יִשְׂרָאֵל, כְּמוֹ מִצְוַת קִדּוּשׁ בְּכוֹר בְּהֵמָה טְהוֹרָה, שֶׁהוּא נוֹהֵג בָּאָרֶץ בִּלְבַד, כְּדַעַת קְצָת הַמְּפָרְשִׁים (עי' ב"י סימן שו), בֵּין בִּפְנֵי הַבַּיִת וְשֶׁלֹּא בִּפְנֵי הַבַּיִת, שֶׁנֶּאֱמַר (דברים יד כג) וְאָכַלְתָּ לִפְנֵי יְיָ אֱלֹהֶיךָ מַעְשַׂר דְּגָנְךָ וְגוֹ' וּבְכֹרוֹת בְּקָרְךָ וְצֹאנֶךָ. וְדָרְשׁוּ זִכְרוֹנָם לִבְרָכָה (תמורה כא, ב) מִמָּקוֹם שֶׁאַתָּה מֵבִיא מַעֲשֵׂר, דְּהַיְנוּ אֶרֶץ יִשְׂרָאֵל, אַתָּה מֵבִיא צֹאן וּבָקָר. וּמִי שֶׁהֵבִיא מִחוּצָה לָאָרֶץ בְּכוֹר לָאָרֶץ אֵין מְקַבְּלִים מִמֶּנּוּ, וְלֹא יִקְרַב דְּחֻלִּין גְּמוּרִין הוּא. וְהַכֹּל חַיָּבִים בְּמִצְוָה זוֹ (רמב"ם שם ה"ז) כֹּהֲנִים, לְוִיִּם וְיִשְׂרְאֵלִים, שֶׁנֶּאֱמַר (דברים טו יט) כָּל הַבְּכוֹר אֲשֶׁר יִוָּלֵד וְגוֹ'. וְאַף עַל פִּי שֶׁנִּפְטְרוּ כֹּהֲנִים וּלְוִיִּם מִפִּדְיוֹן בְּכוֹר אָדָם וּפֶטֶר חֲמוֹר, כְּמוֹ שֶׁכָּתַבְנוּ בְּכָל אֶחָד מֵהֶם בְּסֵדֶר זֶה (מצוה שצב), וּבְסֵדֶר בֹּא אֶל פַּרְעֹה (מצוה כב) חַיָּבִים הֵם בָּזוֹ. וְהָעוֹבֵר עַל זֶה וּפָדָה בְּכוֹר בְּהֵמָה טְהוֹרָה, אַף עַל פִּי שֶׁלֹּא הוֹעִילוּ לוֹ מַעֲשָׂיו וְאֵינוֹ פָּדוּי, אֶלָּא בִּקְדֻשָּׁתוֹ הוּא כְּמוֹ שֶׁהָיָה עָבַר עַל לָאו, שֶׁלְּעִנְיַן הַעֲבָרַת הַלָּאו לֹא אִכְפַּת לָן אִי אַהֲנוּ מַעֲשָׂיו אוֹ לֹא, וְכִדְאִיתָא בִּתְמוּרָה פֶּרֶק רִאשׁוֹן (ד, ב) בְּמַחְלֹקֶת אַבַּיֵּי וְרָבָא. אֲבָל אֵינוֹ לוֹקֶה, לְפִי שֶׁאֶפְשָׁר לַעֲבֹר עָלָיו מִבְּלִי מַעֲשֶׂה.
And this commandment is practiced in the Land of Israel, like the commandment of sanctifying the firstborn pure animals, which is only practiced in the Land of Israel, according to some commentators (see Beit Yosef, Yoreh Deah 306) — both when the Temple [is standing] and when the Temple [is not standing] — as it is stated (Deuteronomy 14:23), “And you shall eat before the Lord, Your God, the tithes of your grain, etc. and the firstborn of your cattle and your sheep.” And they, may their memory be blessed, expounded [it to mean] (Temurah 21b), from the place that you bring your tithes — which is the Land of Israel — you shall bring your sheep and cattle. And if one brought a firstborn animal from outside the Land, they would not accept it from him and it may not be sacrificed, as it is completely non-sacred. Everyone is obligated in this commandment, priests, Levites, and Israelites, as it stated (Deuteronomy 15:19), “Any firstborn that is born, etc.” (Mishneh Torah, Laws of Firstlings 1:7). And even though the priests and the Levites are exempt from redeeming the firstborn of man and the one that exits the donkey, as we have written about each one of them in this Order (Sefer HaChinukh 392) and in the Order of Bo el Pharaoh (Sefer HaChinukh 22), they are obligated in this. And one who transgressed this and redeemed his firstborn pure animal — even though his actions were not effective and it is not redeemed, but rather it is sacred as it was [before] — he has violated a negative commandment. As regarding the transgression of the negative commandment, [the efficacy of] the violation of a negative commandment does not concern us, as is found in the first chapter of Temurah (Temurah 4b), in the disagreement of Abbaye and Rava. But he is not lashed, as he could transgress it without an act.