A festival not only commemorates the past. Every time the Jewish people keep a festival, they merit to receive new light pouring forth toward them from the heavens.

Celebrating the festivals restores the revelation of the original light:

When the holy Rabbi Moshe Zacuto [1625–1697], may his memory be blessed, discussed [the holiness of the festivals] in his book Tikkun Shovavim, he wrote that this is a mystical [meaning] of “these days are remembered and observed” (Esther 9:28): That when they are remembered below [in this world], they are carried out above…and it is possible that this can be found in the wording [of the blessing] established by the Sages: “Who performed miracles for our ancestors in those days, at this time,” meaning, “in those days” God did great things, pouring forth abundance, salvation, and mercy, and a miracle occurred for them; likewise, “at this time,” the divine abundance of mercy is renewed.

Accordingly, it is possible to understand why the festivals are celebrated even in places where the miracles themselves did not occur:

The Jews in Spain and Africa were not under the rule of Ahashverosh, so why are all Jews today obligated to observe Purim? I, with all humility, have arrived at the resolution of this issue via reasoning or by tradition, and it is in accordance with the way of truth [the Kabbala]: Since every year a great radiance shines brightly on Purim, to the same degree as was seen in the days of Mordekhai and Esther, all of Israel must keep these days of Purim at the appropriate time. (Rabbi Ĥayyim Yosef David Azulai, Lev David 29)