Bamidbar 17:5

ולא יהיה כקרח means in order that he be not as Korah. כאשר דבר ה' ביד משה לו AS THE LORD HAD SPOKEN BY THE AGENCY OF MOSES לו — The latter word is the same as עליו, “with regard to him”, i.e. “with regard to Aaron”: He had spoken to Moses that he and his sons should be priests; therefore a layman, who is not of the seed of Aaron, shall not approach etc. Similarly in every instance of the words לי or לו or להם which are connected with forms of the verb דבר, their meaning is the same as על, “concerning”. A Midrashic explanation is that לו, “with regard to him”, means: with regard to Korah (not to Aaron). But what, then, is meant by the expression “by the hand of Moses”; why does it not write “unto Moses”? It is used as an intimation to those who rebel against the institution of the priesthood: that they will become stricken with leprosy, just as Moses was stricken with it on his hand, as it is said, (Exodus 4:6) “and he took it (the hand) forth and, behold, it was leprous, white as snow”. And on account of this (that he insisted on offering incense in spite of the priests’ protest) Uzziah was stricken with leprosy (II Chronicles 26:19) (Midrash Tanchuma, Tzav 1 on צו; cf. also Sanhedrin 110a and Rashi on Isaiah 6:4).

זִכָּר֞וֹן לִבְנֵ֣י יִשְׂרָאֵ֗ל לְ֠מַ֠עַן אֲשֶׁ֨ר לֹֽא־יִקְרַ֜ב אִ֣ישׁ זָ֗ר אֲ֠שֶׁ֠ר לֹ֣א מִזֶּ֤רַע אַהֲרֹן֙ ה֔וּא לְהַקְטִ֥יר קְטֹ֖רֶת לִפְנֵ֣י יְהֹוָ֑ה וְלֹֽא־יִהְיֶ֤ה כְקֹ֙רַח֙ וְכַ֣עֲדָת֔וֹ כַּאֲשֶׁ֨ר דִּבֶּ֧ר יְהֹוָ֛ה בְּיַד־מֹשֶׁ֖ה לֽוֹ׃ {פ}

to be a memorial to the children of Yisra᾽el, that no stranger, who is not of the seed of Aharon, come near to offer incense before the Lord: that he be not like Qoraĥ and his company: as the Lord said to him by the hand of Moshe.