Hilchos Lashon Hara, Opening – Negative commands (3)
The speaker also transgresses the verse (Devarim 24:8), “Beware of the plague of tzara’as to guard exceedingly and to do.” The Sifra explains that when the Torah says to “guard exceedingly,” it means that one should not forget to be careful from lashon hara so that tzara’as does not afflict you because of these words.