וְרֵאשִׁית֩ כָּל־בִּכּ֨וּרֵי כֹ֜ל וְכָל־תְּר֣וּמַת כֹּ֗ל מִכֹּל֙ תְּרוּמ֣וֹתֵיכֶ֔ם לַכֹּהֲנִ֖ים יִֽהְיֶ֑ה וְרֵאשִׁ֤ית עֲרִסֽוֹתֵיכֶם֙ תִּתְּנ֣וּ לַכֹּהֵ֔ן לְהָנִ֥יחַ בְּרָכָ֖ה אֶל־בֵּיתֶֽךָ׃
Igualmente as primícias de todos os primeiros frutos de tudo, e toda oblação de tudo, de todas as vossas oblações, serão para os sacerdotes; também as primeiras das vossas massas dareis ao sacerdote, para fazer repousar uma bênção sobre a vossa casa.
Shenei Luchot HaBerit
Both the commandment of ציצית and that of חלה, are described as ראשית , "heads." In the case of חלה, the Torah speaks about מראשית עריסותיכם, that it is to be taken "from the first part of your doughs" (15,21). Bereshit Rabbah explains that word as meaning "on account of the Challah." The Rekanati describes the mystical dimension of this commandment as being the fact that Israel the nation is called ראשית relative to other nations. This does not only mean that Israel is first, but also that Israel is separate from other nations. It is necessary when putting the dough inside the oven to separate the חלה from the flames of the oven so as not to confront the מדת הדין הקשה, the attribute of Justice in its greatest intensity. This is the meaning of the expression תרומה לה', i.e. a gift to the attribute of Mercy which is mentioned in 15,21. This is the deeper meaning of the statement in the Midrash i.e. "בראשית" on account of that gift which is called ראשחץ. Blessing devolves upon the world because of the fulfillment of this commandment. The reason the חלה is to be given to the כהן is so that blessing will come to rest on your houses. Thus far the Rekanati.