Every festival reveals the will of God and reinforces the awareness that the world does not operate according to nature, but according to His will.

The revelation of [God’s] will is through the festivals. Because each festival proclaims and reveals the will, the fact that everything behaves according to His will alone. This is the aspect of “holy convocation,” [or holy proclamation,] as the festival is holy, and it proclaims the will [of God], since on every festival God performed awesome signs for us, which are the very opposite of nature, and through this, the will was revealed, that everything is in accordance with His will, and there is no natural necessity at all. On Passover, it was the exodus, that He took us out of Egypt with awesome signs. On Shavuot, it was the giving of the Torah, that He gave us the Torah with awesome signs. On Sukkot, it was the presence of the surrounding clouds of glory. Therefore, each and every festival proclaims the will, in the sense of a “holy convocation,” as mentioned above. (Rabbi Naĥman of Breslov, Likutei Moharan Tinyana 4:6)

“A person on a festival must [dedicate himself to] either eating and drinking or to sitting and studying” (Pesaĥim 68b), because through eating and drinking in the physical realm, the soul is able to cling to the spiritual. (Rabbi Yaakov Yosef of Polnoye, Ben Porat Yosef, Noah)

Therefore, the festivals were called good days [yamim tovim], because through them, heavenly good [tov] was revealed. (Rabbi Zev Wolf of Zhitomir, Or HaMe’ir, Bo)

Further reading: For more on miracles and their meaning, see p. 213.