וַיֹּ֤אמֶר יְהוָה֙ אֶל־מֹשֶׁ֔ה אֱמֹ֥ר אֶל־הַכֹּהֲנִ֖ים בְּנֵ֣י אַהֲרֹ֑ן וְאָמַרְתָּ֣ אֲלֵהֶ֔ם לְנֶ֥פֶשׁ לֹֽא־יִטַּמָּ֖א בְּעַמָּֽיו׃
Der Herr sprach zu Mose: Sprich zu den Priestern, den Söhnen Aarons, und befiehl ihnen: An keiner Leiche soll der [Priester] sich verunreinigen in seinem Volke.
Tiferet Shlomo
Hashem told Moshe to tell the Kohanim that they're not allowed to become impure. Rashi explains that the double expression here indicates the older Kohanim should inform the younger Kohanim about this. This is eluding to the following: it says in the Mishna that "the wool and hooves and other parts of the sheep, when attached, is brought up to the Altar--however, the waste isn't brought up." To understand this, we need to preface about the power of tzaddikim. From their mouths we live and anyone who is attached to them will never be forsaken; rather he will be elevated and be included in their service of Hashem. This is the meaning of our prayers: "may Hashem bless those who are G-d-fearing, the old with young." Like it says in the Torah "I ate my sugar cane with my sugar." This is the meaning of the Mishna that the wool ascends to the Altar as long as it's attached, even if it's disgusting and has a foul odor--it will also ascend to Hashem. The waste cannot ascend, however; waste also means separation. If you separate from the tzaddik, chas veshalom, you can never ascend ever again. This was revealed to us by the Baal Shem Tov in his generation, and so in all subsequent generation til Moshiach's coming, all those who cleave to tzaddikim will be elevated and will not be pushed aside. This is the meaning of the Rashi: this is to encourage tzaddikim that they should elevate the smaller people of the generation to Hashem. This is what Yosef was alluded to when he said "you will not see my face without you bringing your brother with you [unless they bring Binyomin]"-- according to your opinion that I [Yosef] am low in your eyes (as they felt he deserved the death penalty chas veshalom, therefore he told them to not to leave him alone since he should be elevated him with them). That's the meaning of the Rashi.