Талмуд к Шмот 4:30

The wise person does not speak before one who is greater than him in wisdom.
From whom do we learn this? From Moses, as it says (Exodus 4:30), “Aaron repeated all the words that the Eternal had spoken to Moses, and he performed the signs in the sight of the people.” And who was the appropriate person to say all these things, Moses or Aaron? One would assume Moses, for Moses had heard them from the mouth of the Almighty, whereas Aaron had heard them just from Moses! However, Moses said to himself: Can I speak in place of my older brother while he is standing right there? Therefore, he told Aaron to speak, as it says (Exodus 4:30), “Aaron repeated all the words that the Eternal had spoken to Moses.”
And he does not interrupt his fellow.
This is Aaron [as it says (Leviticus 10:19), “Then Aaron spoke…see, this day they brought their sin offering and their burnt offering.” But] he was quiet until Moses had finished speaking, and he did not tell Moses to cut his words short. Only afterward did he say to Moses, “See, this day they brought their sin offering and their burnt offering,” but we are in mourning [and cannot eat of the offerings]. And some say that Aaron pulled Moses aside and said to him, “Moses my brother, tithes are the least important of the offerings, and it is still forbidden for a mourner to eat them. A sin offering is the most important of the offerings, so all the more so is it forbidden for a mourner to eat it! Immediately, Moses admitted that [Aaron] was right, as it says (Leviticus 10:20), “And when Moses heard this, it was good in his eyes.” (And in the eyes of the Almighty.)
We learn also from the fact that Moses became angry with Elazar and Itamar, Aaron’s sons. From this, they say that when a person [makes a celebration] for his students, he turns his attention to the greatest of them. But when he becomes angry with them, he directs his anger to the lowliest among them, as it says (Leviticus 10:16), “And he became angry with Elazar and Itamar.” This shows that he was actually angry with Aaron as well.
Aaron was older than Moses, but the Eternal is greater than Aaron! So why didn’t the Eternal speak to Aaron? Because he did not have his sons stand guard. Because if he had put Elazar and Itamar on guard, then he could have kept Nadav and Avihu from sinning.
We learn also from Abraham our forefather, who prayed for the men of Sodom. The Holy Blessed One said to him (Genesis 28:26), “If I find fifty righteous people in Sodom, I will save the whole place for their sake.” But the One who spoke and brought the world into being already knew full well that if there were even three or five righteous people in Sodom, it would have been saved. Yet the Holy Blessed One waited until Abraham finished talking, and only afterward replied, as it says (Genesis 18:33), “When the Eternal had finished speaking to Abraham, He departed…” (as if the Eternal had said to Abraham, see, now I am released, as it says [at the end of the verse]), “…and Abraham returned to his place.”