The two brothers worked well together and consulted one another about what to say and how to say it. When God said, in the plural, “Speak to all the congregation of Israel…” (Ex. 12:3), they were both on the same spiritual wavelength and it appeared that they were both speaking (Rashi, quoting the M’chilta).
This is real brotherliness, real collegiality, without jealousy, rivalry or jockeying for position – a rare blessing. Rabbinic sources apply Psalm 85:11 to Moses and Aaron – “Mercy and truth are met together; righteousness and peace have kissed one another”.
Brotherly love, understanding and co-operation is also the ideal for international relations, when nations can say, “Have we not all one Father? Has not one God created us?” (Mal. 2:10).
At present, the most that nations are usually prepared to do is to co-operate for reasons of expediency, when it is in their joint interest to do so. That’s already an achievement, but in messianic times they will rise to a higher level and kiss one another in righteousness and peace.