Shavua Tov. Today's Parsha discusses both the death of Miriam and the loss of water in the desert, and the death of Aharon and the loss of the ענני הכבוד, the Clouds of Glory in his merit.
The ענני הכבוד represent the idea of Hashem's constant protection. In the desert, these magical clouds were a source of literal protection from any enemy of Israel.
The Torah says that when the כנעני heard of Aharon's death, he saw it as an opportunity to attack Israel. The Talmud in Rosh Hashana says that the כנעני was a euphemism for all evil. This included Satan, עין הרע and יצר הרע, and throw in עמלק for good measure.
The message is that Evil saw an opening to come and try to harm עם ישראל when there was a breach in protection with the loss of the ענני הכבוד. We must learn from this to constantly insulate ourselves with the proper thoughts and action and eliminate all negative thinking. If we don't, we leave ourselves open for bad stuff, חס ושלום. Be strong and we will keep Evil far away from us.