“A leafy olive tree beautiful with shapely fruit; amid the sound of great commotion He has set fire to it and its branches were broken (Jeremiah 11:16). Yehoshu’a son of Levi said: Just as the olive tree’s leaves do not fall neither in winter or summer so too Israel will always remain in this and the world to come [cf. Zohar 1:116a]….
Why is Israel compared to an olive? To teach that just as the olive does not produce its oil until it is crushed, so too Israel does not return except through suffering” (BT Menakhot 53b).
“Rabbi Shim’on son of Laqish said: Covenant is mentioned with regards to salt, and covenant is said with regard to suffering: Covenant is said with regards to salt, as is written: And every offering of your grain you shall season with salt (Leviticus 2:13). Covenant is said with regard suffering, as is written: [And it shall be, if you do not heed the voice of YHWH your God to keep to do all His commands and His statutes that I charge you today, all these curses will come upon you and overtake you… (Deuteronomy 28:15).] These are the words of the Covenant (ibid., 69). Just as the covenant said with regard to salt, the salt sweetens meat, so too the covenant mentioned with regard to suffering, the suffering washes away all the crimes of man.
It has been taught: Rabbi Shim’on son of Yoḥai says: The blessed Holy One gave Israel three precious gifts, and all of them were given only through suffering: Torah, the land of Israel, and the World that is Coming. How do we know this of Torah? As is said: Happy the man whom Yah chastises, and whom מִתּוֹרָתְךָ (mitoratekha), from His teaching, He instructs (Psalms 94:12). The land of Israel—as is written: As a man chastises his son YHWH your God chastises you (Deuteronomy 8:5), and after that it is written: For YHWH your God is about to bring you to a goodly land (ibid.). The World that is Coming—as is written: For a mitsvah a lamp and a teaching a light, and the way of life—stern rebukes (Proverbs 6:23)” (BT Berakhot 5a).