Symbolism of the Rainbow

While walking to shul this past on a recent erev Shabbat, the one upon which the 9th of Av fell this year, I saw a faint rainbow in the clouds. This led to some mind-wandering on my walk, which ended with me pondering the following question:

Why is the rainbow the symbol of the covenant between God and Noach in the 9th Perek of Bereishet:

יב: וַיֹּאמֶר אֱלֹקים, זֹאת אוֹת-הַבְּרִית אֲשֶׁר-אֲנִי נֹתֵן בֵּינִי וּבֵינֵיכֶם, וּבֵין כָּל-נֶפֶשׁ חַיָּה, אֲשֶׁר אִתְּדֶ--לְדֹרֹת, עוֹלָם
12: And God said: 'This is the token of the covenant which I make between Me and you and every living creature that is with you, for perpetual generations
...
טז: וְהָיְתָה הַקֶּשֶׁת, בֶּעָנָן; וּרְאִיתִיהָ, לִזְכֹּר בְּרִית עוֹלָם, בֵּין אֱלֹקים, וּבֵין כָּל-נֶפֶשׁ חַיָּה בְּכָל-בָּשָׂר אֲשֶׁר עַל-הָאָרֶץ
16: And the bow shall be in the cloud; and I will look upon it, that I may remember the everlasting covenant between God and every living creature of all flesh that is upon the earth:

Why is the rainbow chosen as the symbol of this covenant? Why not a torrential downpour? A terrible storm? A dove? A large boat? Why specifically a rainbow?

I propose the following:

The generation of the flood committed many sins - of violence and thievery and so on. Their sins were rooted in Sinat Chinam (Bereishit Rabbah 38:6) - in 'free' hatred (I will discuss that concept further in a future post).

What is one, if not the, root cause of Sinat Chinam? When one sees other people as completely separate from oneself - when any difference from oneself in another makes one's fellow an 'other' - a non-person.

A rainbow, to the human eye, looks like it is made of several distinct and separate bands of color. In reality, the color changes continuously*, without borders, along the width of the rainbow.

This is the symbol for Man - that we should look upon the rainbow, and perceive the symbol, to remember that as different as we may be from one-another there is no wall between us, there is no division that brings forth such a differentiation as between 'person' and 'other' - and when this is abrogated, Mankind once more walks the path of destruction.

May we all endeavor to bring forth, and merit to see, the day when all of humanity will hold this principle in their minds, and teach it to their children, inductively, for all time.


*For the mathematically inclined:
I note that in reality this is not quite true according to a mathematically rigorous usage of continuity, at least in the typical sense with which it is applied in analysis, due the the fundamental graininess of the universe on the smallest scale. I do not think that this negates the nice symbolism, and one can read not 'continuously' but rather 'without borders or sudden changes' if so desired.