מִקְצֵ֣ה ׀ שָׁלֹ֣שׁ שָׁנִ֗ים תּוֹצִיא֙ אֶת־כָּל־מַעְשַׂר֙ תְּבוּאָ֣תְךָ֔ בַּשָּׁנָ֖ה הַהִ֑וא וְהִנַּחְתָּ֖ בִּשְׁעָרֶֽיךָ׃
Então virá o Levi – pois ele não tem parte nem herança contigo – e o convertido, o órfão e a viúva que estão dentro de tuas portas, e comerão até se fartarem, para que Yehovah, teu Elohim, te abençoe em toda obra das tuas mãos que fizeres. {ס}
Siftei Chakhamim
Every form of the word קץ means “the end.” It is obvious that קץ means “end,” as Onkelos translates it. However, [Rashi is answering the] question: Why does Scripture write the word ימים? It would be understandable if קץ did not [always] mean “end,” but [also can mean] “some of,” as in מקצה אחיו, “From some of his brothers” (47:2). Accordingly, here it mentions ימים to indicate that it was two full years, not part of two years. But if מקץ always means “end,” why does Scripture write ימים? Rashi answers: We might think מקץ means “some of,” and it always means this, unless it is evident otherwise from the verse. That is why it is written here ימים — to show that it means “end,” and not “some of.” Consequently, קץ always means “end.” For it is evident here that קץ means “end,” and we make a gezeirah shavah between קץ [written here, and any other instance of] קץ. Thus Rashi says, “And [henceforth,] every form of the word קץ means ‘the end’.” So it seems to me, as opposed to Re’m’s explanation, that Rashi says every form of the word קץ means “the end” because Rashi wishes to distinguish קץ from קצה. This is because קצה sometimes means “end,” as in: “At the end (מקצה) of three years” (Devarim 14:28). And it sometimes means “side,” as in: “One cherub on this side (מקצה)” (Shemos 25:19). And it sometimes means “some of,” as in: “From some of (מקצה) his brothers” (47:2). Although [the word קץ] appeared several times previously in Scripture, [and Rashi did not comment there,] this is not problematic, as many similar cases exist [where Rashi does not explain a word the first time it appears]. Re’m writes: We need not object that it says, “At the קץ of seven years, you are to make shemitah” (Devarim 15:1), which apparently means at the beginning of shemitah, as it is written, “But in the seventh year you must let it rest” (Shemos 23:11). For [the answer is:] The verse in Devarim is speaking of releasing debts (השמטת כספים), and this is at the end of shemitah.
Ibn Ezra
At the boundary of seven years you will arrange a release denotes the beginning of the year, as is corroborated by the passage of “assemble the people” [31: 12]. The passage is connected to the previous one because, having mentioned that the Pauper’s Tithe belongs to the Levite, and the alien, and the orphan, and the widow [cf. 14: 29], it is now logical to discuss the general release. release [Hebrew: shmiṭṭah] from “drop her” [Hebrew: shimṭuhah] [II Kings 9: 33]: i.e., they released her, and she fell.
Tur HaArokh
מקץ, Rashi, following Onkelos, translates this as “at the end.” The reason he interprets the word as meaning “at the end,” is so we should not misunderstand its meaning to be “at the beginning,” as in Deut. 14,28 מקצה שלש שנים, where it means “the beginning of the third year.”