Even though Noach was a tzaddik; nevertheless, he resembled the olive that keeps its oil trapped inside. He did not make an effort to venture out and teach his generation the ways of the Torah and its mitzvot. In contrast, Moshe Rabeinu resembled olive oil; he taught Torah to all of Yisrael. Thus, in his gilgul, he rectified Noach’s flaw. 

HKB”H wanted them to light the menorah with olive oil, so that we would understand that the purpose of studying Torah is to enlighten other people—like olive oil that emerges from the olive and promotes memory.  

Hence, HKB”H explains that the reason for the mitzvah of taking olive oil is “to keep the lamp burning continuously”—because
it is a wonderful device for ensuring the perpetuation of the Torah. 

We can now comprehend the great significance of the dove’s deed after the mabul: “The dove returned to him in the evening, and—behold—an olive leaf was in her mouth.”  

 After the dove saw that the water had receded from the surface of the earth, she wanted to alert Noach to the necessary tikun he was obliged to perform. Therefore, she brought him an olive leaf, hinting to him that he resembled an olive; he was keeping his oil
confined and trapped within himself.  

 Furthermore, she was indicating to him that he would have to reincarnate as Moshe; Moshe would make amends for him by
kindling the menorah with the oil of the olive—allowing the oil to emerge for the benefit and enlightenment of others. 

 At this point, we can finally appreciate the cryptic wisdom of our sages in the Midrash: HKB”H said, “Just as the dove brought light to the world, so, too, you, who are compared to the dove, brought olive oil and lit the lamp before Me, as it states: “And you shall command . . . that they shall bring you oil.”