These are Aharon and Moshe whom HaShem said to them: take B'nei Israel out of Egypt in their multitudes. They, the ones speaking with Pharaoh the king of Egypt (in order) to take B'nei Israel out from Egypt, these are Moshe and Aharon." (Shemot 6:26-27)

Rashi explains: There are instances in which the Torah gives precedence to Aharon before Moshe, and there are instances where it gives precedence to Moshe before Aharon, to tell you that they are considered equal.

When should Moshe precede Aharon, and when should Aharon precede Moshe?

It can be said that when there was a need to speak with Am Israel, then Aharon preceded Moshe, as it says: "And he will speak for you to the nation and he will be a mouth (speaker) for you and you will be his master." And therefore it is written: "These are Aharon and Moshe whom HaShem said to them: take B'nei Israel out etc…"

But when they had to speak with Pharaoh, Moshe preceded Aharon, since it is written: "And HaShem said to Moshe: see, I have made you a lord to Pharaoh, and Aharon your brother will be your prophet." And indeed it is written: "They, the ones speaking with Pharaoh the king of Egypt to take B'nei Israel out from Egypt, these are Moshe and Aharon." 

Regarding Rashi's words: "to tell you that they are considered equal" – we can add and expound:

There is a human tendency for one to consider himself great, important and deserving of respect, at very least in comparison to others. Whether the basis for comparison is intelligence or good middot; whether the issue is Torah or yichus (lineage) or any other positive attribute, most people tend to see themselves (at least) one level above their fellow men.

Therefore it is very difficult for one person to feel equal to another, and as a result, when people work together, this is often accompanied by tension, jealousy and conflict.

This is not the case with Moshe and Aharon.

Only one month after the exodus from Egypt, when the nation complains: "For you have taken us out to this desert to let all this populace die of starvation" Moshe and Aharon answer: "And what are we (of what importance) that you should complain about us?"

One who does not feel any self-importance whatsoever can certainly act together with anyone, as he feels no superiority to his fellow man.

May we ourselves merit to put into practice all these good middot which are rooted in true modesty and humility, and through this may we succeed in finding grace and good sense and wisdom in the eyes of HaShem and our fellow men.