"And if his offering is a goat" (Leviticus 3:12-15) - it interrupted the matter, so that the goat would not require a fat tail. "And he shall offer from it" - from that which is still attached. "His offering, a fire-offering to the LORD, the fat that covers the entrails and all the fat that is upon the entrails" - what does this teach? That one might think it is lessened from all of them. And it is a logical argument: just as we find with the flock-animal, which was increased regarding the fat tail and increased regarding all of them, but the goat, which is lessened regarding the fat tail - since it is lessened regarding the fat tail, it should be lessened from all of them. Let the herd-animal prove the point, for it is lessened regarding the fat tail and yet increased regarding all of them. No: if you have said this of the herd-animal, which is increased regarding libations, will you say it of the goat, which is lessened regarding libations? Since it is lessened regarding libations, it should be lessened from all of them. Therefore Scripture says "the fat that covers the entrails" - to include all of them. "And the priest shall turn them to smoke" (Leviticus 3:16) - all of them as one. "Bread, a fire-offering for a pleasing aroma; all fat is the LORD's" - to make one liable for misappropriating the fat. In the name of Rabbi Yishmael they said: from the general statement, where it is said, "But the firstling of an ox or the firstling of a lamb or the firstling of a goat you shall not redeem; they are holy; their blood you shall dash upon the altar and their fat you shall turn to smoke" (Numbers 18:17), we have learned of the firstborn that it requires the placing of blood upon the altar. From where do we learn this for the tithe and the Passover-offering? Scripture says, "And the blood of your sacrifices shall be poured out upon the altar of the LORD your God" (Deuteronomy 12:27). I have only the blood; from where the fats? Scripture says "all fat is the LORD's." "An eternal statute" (Leviticus 3:17) - for the everlasting House. "Throughout your generations" - that they shall practice the matter through the generations. "In all your dwellings" - in the Land and outside the Land.
The Goat Offering and All Fat Belongs to the LORD
Yalkut Shimoni on Torah 463:1
(ויקרא ג יב-טו) וְאִם עֵז קָרְבָּנוֹ, הִפְסִיק הָעִנְיָן שֶׁלֹּא תְּהֵא הָעֵז טְעוּנָה אַלְיָה. וְהִקְרִיב מִמֶּנּוּ, מִן הַמְחֻבָּר קָרְבָּנוֹ "אִשֶּׁה לַה' אֶת הַחֵלֶב הַמְכַסֶּה אֶת הַקֶּרֶב וְאֵת כָּל הַחֵלֶב אֲשֶׁר עַל הַקֶּרֶב", מַה תַּלְמוּד לוֹמַר שֶׁיָּכוֹל נִתְמַעֵט מִכֻּלָּם, וְדִין הוּא מַה מָּצִינוּ בְּבֶן צֹאן שֶׁנִּתְרַבָּה בְּאַלְיָה נִתְרַבָּה בְּכֻלָּם, אֲבָל בֶּן הָעֵז שֶׁנִּתְמַעֵט בְּאַלְיָה הוֹאִיל וְנִתְמַעֵט בְּאַלְיָה יִתְמַעֵט מִכֻּלָּם בֶּן הַבָּקָר יוֹכִיחַ שֶׁנִּתְמַעֵט בְּאַלְיָה וְנִתְרַבָּה בְּכֻלָּם, לֹא אִם אָמַרְתָּ בְּבֶן הַבָּקָר שֶׁנִּתְרַבָּה בִּנְסָכִים תֹּאמַר בְּבֶן עֵז שֶׁנִּתְמַעֵט בִּנְסָכִים, הוֹאִיל וְנִתְמַעֵט בִּנְסָכִים יִתְמַעֵט מִכֻּלָּם, תַּלְמוּד לוֹמַר "הַחֵלֶב הַמְכַסֶּה אֶת הַקֶּרֶב", לְרַבּוֹת אֶת כֻּלָּם. (ויקרא ג טז) וְהִקְטִירָם הַכֹּהֵן, כֻּלָּם כְּאֶחָד לֶחֶם אִשֶּׁה לְרֵיחַ נִיחֹחַ כָּל חֵלֶב לַה', לְחַיֵּב עַל הַחֵלֶב מְעִילָה, מִשּׁוּם רַבִּי יִשְׁמָעֵאל אָמְרוּ, מִכְּלָל שֶׁנֶּאֱמַר "אַךְ בְּכוֹר שוֹר אוֹ בְכוֹר כֶּשֶׂב אוֹ בְכוֹר עֵז לֹא תִפְדֶּה קֹדֶשׁ הֵם אֶת דָּמָם תִּזְרֹק עַל הַמִּזְבֵּחַ וְאֶת חֶלְבָּם תַּקְטִיר", לָמַדְנוּ לִבְכוֹר שֶׁטָּעוּן מַתַּן דָּמִים לַמִּזְבֵּחַ. לְמַעֲשֵׂר וּלְפֶסַח מִנַּיִן תַּלְמוּד לוֹמַר (דברים יב, כז) "וְדַם זְבָחֶיךָ יִשָּׁפֵךְ עַל מִזְבַּח ה' אֱלֹהֶיךָ" אֵין לִי אֶלָּא דָּמִים, חֲלָבִים מִנַּיִן תַּלְמוּד לוֹמַר "כָּל חֵלֶב לַה'". (ויקרא ג יז) חֻקַּת עוֹלָם, לְבֵית עוֹלָמִים לְדֹרֹתֵיכֶם, שֶׁיִּנְהֲגוּ הַדָּבָר לְדוֹרוֹת בְּכֹל מוֹשְׁבֹתֵיכֶם בָּאָרֶץ וּבְחוּצָה לָאָרֶץ.