כָּל מַחֲלֹקֶת שֶׁהִיא לְשֵׁם שָׁמַיִם, סוֹפָהּ לְהִתְקַיֵּם. וְשֶׁאֵינָהּ לְשֵׁם שָׁמַיִם, אֵין סוֹפָהּ לְהִתְקַיֵּם. אֵיזוֹ הִיא מַחֲלֹקֶת שֶׁהִיא לְשֵׁם שָׁמַיִם, זוֹ מַחֲלֹקֶת הִלֵּל וְשַׁמַּאי. וְשֶׁאֵינָהּ לְשֵׁם שָׁמַיִם, זוֹ מַחֲלֹקֶת קֹרַח וְכָל עֲדָתוֹ:
Jeder Streit, der im Namen Gottes geführt wird, hat zuletzt bleibenden Erfolg; der aber nicht im Namen Gottes geführt wird, hat keinen bleibenden Erfolg. Welches ist ein Streit, der im Namen Gottes geführt wird? Das ist der Streit von Hillel und Schammai; der nicht im Namen Gottes geführte, das ist der Streit von Korach und seiner ganzen Rotte.
Kli Yakar
“And God called the firmament Heaven.” God did not want it to be called by the name “rakia” [firmament] because this name indicates separation and division, as per and they flattened the gold into thin plates (Exodus 39:3) — for that which was to cover the earth. Since any rakia is a covering that separates between two things, and for this reason, it does not state “that it was good” on the second day, since disagreement was created on it, since there is no good except in a place where we find unity. And therefore on the third day, “that it was good” is stated twice: once for the work of the third day and once for the finishing of the water, that has an aspect of unity in it, as it is stated, let the waters gather to one place (Genesis 1:9), and because of this unity, “that it was good” is mentioned. But on the second day — from which comes out all differences, and which is the beginning of all difference and disagreement — “that it was good” was not said about it. And God did not want that [the sky] should be called firmament, which indicates a cover that separates and divides between brothers, and it was called with the name heavens [shamayim], which indicates peace, since shamayim is composed of the words fire [esh] and water [mayim], who made peace between themselves and joined together, and from them was created heavens. And this is what the Rabbis, of blessed memory, state (Avot 5:17), “Any disagreement that is for the sake of the heavens [shamayim], etc.,” which means to say that a disagreement whose purpose is peace, as is the teaching of the name shamayim, and [this is] easy to understand. And according to its simple meaning, “that it was good” was not stated on the second day, since there was no new creation on it, since the firmament was already created on the first day, and the reason for [no creations happening on the second day] is because the second day is the beginning of all difference and division; hence the Holy One, blessed be He, did not want to implant a nature of difference in any creation.