What was the sign or token for the rebels and why?
Answer From The Annual Reading Schedule - Week 36 Notes For Numbers: The rod of Aharon (Aaron), of the house of Lewi, budded with ripe almonds, placed before the Witness/Testimony to show that Aharon and His Sons were the ones chosen by Yahweh and to put an end to the grumblings against Yahweh so that they do not die (Numbers 17). This was also possibly important so that the children of Yisra'el (Israel) realized it wasn't Mosheh (Moses) and Aharon (Aaron) lifting themselves up, but that Yahweh had been the one to choose Aharon and his sons and the tribe of Lewi.