We all know when a teacher starts listing off rules we automatically start tuning every word out, because it sounds like they are saying bla bla and seems whatever comes out of their mouth doesn’t seem applicable. But the moment the teacher says “don’t go past the red tape because Sam from the grade above you did and got seriously injured and had to stay in the hospital for a week”, all of a sudden everyone’s ears perk up and no one would dare breaching that rule. Only if the teacher would bring a real life example, would everyone be deterred, take it seriously and fully comprehend that the rule is real, not just some abstract saying.
The parsha opens up with “G-d spoke to Moshe after the two sons of Aharon died when they approached G-d. And G-d said to Moshe, tell Aharon, your brother, he cannot come into the Sanctuary at any time he wants…”. Aharon’s had two sons who died because they entered the Sanctuary on their own volition and gave sacrifices according to how they wanted to serve G-d, and not how G-d commanded it. Therefore right before G-d gives Aharon the commandments on how he has to enter the Sanctuary, He prefaces it with a real life example of repercussions of not following the laws, which Aharons own sons had received.
G-d had to give a real life example here specifically, to highlight how important it is to serve G-d on His terms and not on one’s mere whims and convictions. Having a relationship with G-d isn’t about making Him fit into our lifestyles, rather it should be us making our lifestyles fit what G-d wants of us.