וידם אהרן (שמיני י:ג)

Rashi says that because Aaron remained silent, he was rewarded that Hashem spoke to him directly, introducing the parsha of שתויי יין (when Kohanim may or may not do their service in the Mishkan).

The above can be better understood with the Gemara (שבת ל:ב) that says: The Shechina (Divine presence) can only rest during Simcha shel Mitzvah (the joy of doing a mitzvah) and not when one is sad.

So, even though Aaron had a right to mourn over the loss of his two children, he accepted it with simcha – blocking out all sadness – he, therefore, merited to hear Hashem speak to him.