From the very beginning of Parashat Korah, the Torah places unusually strong emphasis on his lineage.  He is introduced not just with the standard patronym, but with three generations of ancestors, tracing him back to the tribal founder, Levi. A midrash in Bemidbar Rabbah picks up on this extended chain of forebears and suggests that it is there to alert us to the underlying motivation for Korah’s confrontation with Moshe.