Likutei Moharan 42:2/ליקוטי מוהר"ן מ״ב:ב׳

12. Also through faith in the sages—by believing that all the things they say and do are not simple but contain deep mysteries, one clothes the rainbow in radiant garments. Then, “I will see her and remember the everlasting covenant.” For the tzaddik corresponds to the rainbow, as Rabbi Shimon ben Yochai said to Rabbi Yehoshua ben Levi: “Was a rainbow seen during your lifetime?” (Ketuvot 77b).

2And in the holy Zohar it is brought: Someone whose devotions are intended to illuminate the Matron, so that he removes her dark garments which stem from the [Torah’s] simple meaning and adorns her in garments of radiant colors which stem from the Torah’s mysteries, of him it is written: “I will see her and remember the everlasting covenant.” For light is called a secret. Thus at that time his anger at his son disappears, “the king’s wrath abated.”