"And Moshe inquired about the goat of the sin-offering and behold it was burnt, and he was angered at Elazar and Itamar, Aharon's remaining sons, saying: Why did you not eat the sin – offering in the holy place… and Aharon said to Moshe… and Moshe heard and it was good in his eyes."
 

In our parsha, as an aside to the story of Nadav and Avihu, the Torah tells us briefly about the disagreement between Moshe and Aharon over the laws of eating a sin-offering by an onen (one whose dead lies before him). When Moshe Rabbenu hears that Aharon and his sons burned the goat which was the sin-offering, he becomes angry with Elazar and Itamar, Aharon's remaining sons, and he addressed them with words of rebuke: "Why did you not eat the sin-offering in the holy place?" The one who answers him is not Elazar or Itamar, but Aharon himself explains to Moshe his reason, that an onan is not permitted to eating this sin-offering (and our Sages differed over what kind of sin-offering was the issue, and what were the reasons of Moshe and Aharon). When Moshe hears Aharon's answer, the Torah concludes: "And Moshe heard, and it was good in his eyes."
 

And it seems that a number of very important halachot regarding the proper way to rebuke can be learned from this parsha, which is small in quantity (length) but great in quality (importance).
 

1. The one who was responsible for performing the sacrifices was Aharon, and not his sons. Therefore, Moshe's rebuke should have been directed toward Aharon and not toward his sons. So why does Moshe specifically rebuke the sons? Rashi explains that Moshe did this out of deference for Aharon.

And we can add to this, that not only was the rebuke directed toward the sons and not Aharon, but also the anger which was aroused in his heart was aroused only at the sons. In this we see Moshe's outstanding character traits and his control over his emotions – that it was out of the question for Moshe to be angry with Aharon, his older brother whom he was obliged to honor.
 

2. Moshe Rabbenu rebukes Elazar and Itamar "saying" (le'emor – to say) and Chazal explain that he asked them to respond. Moshe did not suffice with informing them of their transgression from his point of view, but he wanted to hear their reason and explanation, and didn't rely exclusively on the correctness of his claims.
 

3. The charge was directed at Elazar and Itamar, and presumably they heard from Aharon the reason that it was a mitzvah to burn this sacrifice. Nevertheless they refrained from answering before Aharon their father.

4. After Moshe hears their rationale, he doesn't argue, but acknowledges the correctness of their action and is not embarrassed to admit his mistake.   

All these things stem from one source. When one is overcome with anger, and takes it out by spewing out rebuke, he loses control of himself and over the proper way to express his anger. He is unwilling to listen to any response or excuse, and he certainly will not be quick to admit his mistake. But Moshe's answer to his nephews / students emanated from his genuine love and concern for them, and this is the source of his behavior.

And I saw a fantastic "hint" in the name of the Ben Ish Chai, that the first letters of Moshe Rabbenu's words of rebuke, "מדוע לא אכלתם את החטאת במקום הקודש" are "מלא אהבה"  -full of love!

So we see that Moshe, like his brother Aharon, exemplified the axiom: "Love your fellow men" and through this – "bring them close to Torah."

May our hearts be filled to the brink with love for each and every one of Am Israel, and may we all merit to be among the talmidim of Moshe and Aharon and to cleave to their way – "Love your fellow men and bring them close to Torah."