This parsha discusses the deaths of the sons of Aharon: Nadav and Avihu. Nadav and Avihu died because they knowingly brought a korban into the Kodesh Hakedoshim, a place dedicated for only the Kohen Gadol to bring korbanot to. Hashem spoke to Moshe following their deaths and He used a parable to illustrate his point. A man goes to a doctor and he explains that he is sick. The doctor tells him all of the things he must not do. The same man goes to another doctor for a second opinion, and this doctor advises him not to do these various things in order to avoid death. The man takes the opinion of the second doctor, because with the opinion of the second doctor, he is informed of the aftermath and is given ways to avoid it.
From this parable we learn why Hashem made sure to warn the other Kohanim to be careful. The deaths of Nadav and Avihu have the same effect as the doctor with the second opinion: their deaths provide all of the other Kohanim with not only a list of things they should not do, but an example of the consequences they are trying to avoid.
By: Lexi Sugar