The Midrashim and Commentaries offer various explanations as to the symbolism of the burning bush. The most straightforward seems to be that the fire represents our adversaries who unsuccessfully attempt to consume the Israelites. Certainly an appropriate message these days.
Kli Yakar has an interesting suggestion. The thornbush represents the people who are constantly bickering and snitching. Rashi (2:14) attributed this being Adam l’chaveiro blemish to the ongoing bondage). Even when suffering in inflicted from the outside, the fire of machloket within still rages.
Unfortunately, this message also remains relevant.
Shabbat Shalom