Somewhere Over the Rainbow: Torah as the Pathway to Perception of Hashem's Presence

One of the signature symbols in parshat Noach is the rainbow, which Hashem displays following the mabul (Flood) as evidence of his commitment that He will never again destroy the world with water (Noach 9:13). Initially, the rainbow thus appears to be a positive sign - a covenant evidencing Hashem's commitment to mankind.

However, Rashi states that the appearance of a rainbow actually has negative connotations. Observing that the word "dorot" (generations) in the pasuk (9:12) immediately preceding the introduction of the rainbow is missing letters (i.e., two "vavs"), Rashi explains that the word "generations" is "written 'chaser' [missing letters] since there are generations that do not need this sign [that Hashem won't destroy the world with water] since they are totally righteous like the generation of Chizkiyahu King of Judah and the generation of Rabbi Shimon Bar Yochai." In other words, when a rainbow appears in any generation, it is a sign that there is wickedness in the world, and the generation is deserving of destruction but for Hashem's commitment as evidenced by the rainbow. Indeed, Rabbeinu Yehudah bar Yakar (a teacher of the Ramban) writes in his Peirush HaTefillos Vehaberachos (2:58) that one ought to be inspired to do teshuva upon seeing a rainbow.

Other sources reflect similar ambivalence concerning a rainbow. On the one hand, one makes a bracha upon seeing a rainbow. But once the bracha is made, it is inappropriate to gaze at the rainbow for a prolonged period of time (Chagiga 16a). This is because the rainbow represents the "Shechina" (Divine Presence) (as per the navi Yechezkel, 1:28) (interestingly, there is a natural phenomenon similar to a rainbow called a "glory").

It is also inappropriate to run and tell someone else about a rainbow that one sees since it is like spreading a bad report (that is, the rainbow is a sign that bad deeds are being done, and Hashem is withholding punishment) (Chayei Adam, 63:4) (for full list of "rainbow" sources see here).

What can we learn from this ambivalence? What can we learn from rainbows?