The Chizkuni (31:2) notes that when the Torah introduces us to Betzalel, he is introduced as “Betzalel son of Uri son of Chur”—three generations—yet when the Torah tells us the lineage of Eliav it only mentions one generation “son of Achisomach.” Why was it necessary to mention “Chur” who was Betzalel’s grandfather? Chur was involved in the chet ha’egel in a positive way. When the Jews wanted to create the egel, Chur tried to dissuade them—and was murdered because of this. Therefore, the mishkan which was to be fashioned to atone for the sin of the chet ha’egel, would also be a kapara for his murder. Chur’s name is mentioned in the lineage so that it is also included in the kapara.
When I read this comment, it struck me as a bit odd. Usually we do not go out of our way to bring focus onto the things we did wrong when not necessary. Not only that, the grandson definitely was not involved in the killing of the grandfather, so certainly he should not be the one to be mechaper. However, when you think about this a little bit more, it seems that the answer is rather simple. Part of doing teshuva is looking the sin “straight in the face” and understanding its broad ramifications and the need to do teshuva for all of the negative fallout.
One could possibly have rationalized that each of the two sins were completely separate events. It is true that there was a murder of a Jew, in the backdrop of the sin of the golden calf, but the way to do teshuva on that sin is not independent of doing teshuva for the chet ha’egel. The Chizkuni is teaching us that not only do we have to realize the gravity of the sin, but the context in which it was committed will also inform us how to do teshuva. In other words, if the Jews would have done a complete teshuva for each sin, but had done so separately, that would not have been sufficient. One must bring the background of the sin into the foreground and repent on that, too. Hence by mentioning the death of Chur as a connection to the building of the Mishkan, we have incorporated it into one large sin and the teshuva that is done by building the mishkan can atone for the killing of Chur as well.
Many times people are willing to “own up”. We see from here that we have to take responsibility not only for the main iniquity we have done, but also for all of the incidentals that it encompassed.