הִשָּׁ֧מֶר בְּנֶֽגַע־הַצָּרַ֛עַת לִשְׁמֹ֥ר מְאֹ֖ד וְלַעֲשׂ֑וֹת כְּכֹל֩ אֲשֶׁר־יוֹר֨וּ אֶתְכֶ֜ם הַכֹּהֲנִ֧ים הַלְוִיִּ֛ם כַּאֲשֶׁ֥ר צִוִּיתִ֖ם תִּשְׁמְר֥וּ לַעֲשֽׂוֹת׃ (ס)
Guarda-te cuidadosamente contra a praga da lepra, para observar diligentemente e fazer conforme tudo o que os cohanim, os Levi'im, vos ensinarem, conforme eu lhes ordenei, assim guardareis para fazer.
Rashi
השמר בנגע צרעת TAKE HEED IN THE AFFLICTION OF LEPROSY — take heed that you pluck not out the symptoms of uncleanness (cf. Leviticus ch. XIII.), nor cut out the leprous spot (Makkot 22a).
Chizkuni
השמר בנגע הצרעת, “be most careful with the plague known as tzoraat;” Do not give honor to someone who is great to exempt him from being sent outside of the three camps. Remember what Hashem, your God, did to Miriam, who was the sister of the king and the sister of the Kohein Godol, and even so was quarantined outside the camp for seven days.
Da'at Zekenim
השמר בנגע הצרעת, “be most careful in the matter of a skin affliction.” The reason why the Torah repeats the same warning twice is because this disease is apt to afflict anyone, kings not excepted. King Uzziyahu was afflicted by it, as we know from Chronicles II 26,21. Being afflicted by this disease is most shameful for the person concerned, so that even if he is a king he must remain in isolation and cannot function in his palace and must be obedient to what the priest tells him concerning the length of time of this disease. This is also the reason why the Torah adds that we must remember how Moses’ sister Miriam was afflicted by this disease because she had been guilty of badmouthing her brother Moses. Even though she was socially one of the most highly placed people, the priests had to put her in isolation just like an ordinary person struck by this disease.