1)
What is this Pasuk coming to tell us?
1.
Rashi: Following on from the previouis Pasuk, it teaches us that Hashem placed them in Cherem only after informing them of the sin of which they were guilty. 1
2.
Seforno: The Torah is hinting that Aharon and Miriam did not immediately humble themselves before Hashem (and admit their guilt). 2
1
Rashi: How much more so should a human-being inform his friend what he did wrong before giving vent to his anger.
2
Seforno: In the way that David ha'Melech did - See Shmuel 2, 12:13.