הִשָּׁ֧מֶר בְּנֶֽגַע־הַצָּרַ֛עַת לִשְׁמֹ֥ר מְאֹ֖ד וְלַעֲשׂ֑וֹת כְּכֹל֩ אֲשֶׁר־יוֹר֨וּ אֶתְכֶ֜ם הַכֹּהֲנִ֧ים הַלְוִיִּ֛ם כַּאֲשֶׁ֥ר צִוִּיתִ֖ם תִּשְׁמְר֥וּ לַעֲשֽׂוֹת׃ (ס)
Take heed in the plague of leprosy, that thou observe diligently, and do according to all that the priests the Levites shall teach you, as I commanded them, so ye shall observe to do.
Targum Jonathan on Deuteronomy
Take heed that you cut not into flesh in which there is an ulcer; but make careful distinction between the plague of leprosy and ulceration; between the unclean and clean, according to all that the priests of the tribe of Levi shall teach you: whatever, they prescribe to you be observant to perform.