וְהָ֤יְתָה לּוֹ֙ וּלְזַרְע֣וֹ אַחֲרָ֔יו בְּרִ֖ית כְּהֻנַּ֣ת עוֹלָ֑ם תַּ֗חַת אֲשֶׁ֤ר קִנֵּא֙ לֵֽאלֹהָ֔יו וַיְכַפֵּ֖ר עַל־בְּנֵ֥י יִשְׂרָאֵֽל׃
и ему, и потомку его после него будет завет вечного священства; потому что он ревновал к своему Богу и делал искупление для детей Израиля.'
Tze'enah Ure'enah
“Thus making expiation for the Israelites” [25:13]. He atoned for Israel. From here we learn that the one who kills evildoers, it is as if he brought a sacrifice.5Bahya, Numbers, 25:13.
Rashi
והיתה לו AND IT SHALL BE UNTO HIM — this covenant of Mine shall be unto him —
Midrash Lekach Tov
And it shall be to him and his descendants after him an everlasting covenant of priesthood. These are the twenty-four priestly gifts, in return for his zeal (Isaiah 33:12), "In return for his fervor, he made atonement for his people." It is not only said "made atonement," but "made atonement for the children of Israel." "Made atonement" is mentioned until now, indicating that it continues to atone even for the deceased.