On Chanuka we recite the blessing which praises G‑d for “performing miracles for our ancestors in those days at this time.” Please remind me what’s particular about reciting “at this time”. Also, as far as I remember, the Sages didn’t actually decree observance at the time of the miracle, but rather the year after. How can this be reconciled with the wording “in those days, at this time.”
This is a very timely observation. I hope you’ll find my explanation illuminating!
The festivals of the Torah are like portals connecting to the spiritual worlds through which the influence of each holiday flows year after year, generation after generation, on the very day when the event that holiday commemorates actually occurred. At that time, the Divine Gates are opened and the quality and light particular to that holiday permeate the world.
Thus Pesach radiates the light of redemption, Shavuot that of Torah, Succot that of rejoicing and the High Holidays radiate the light of repentance and forgiveness.
There are other days which are festivals not ordained by the Torah, such as Chanuka and Purim, which also commemorate spectacular miracles and acts of salvation. These days were judged by either Prophets or outstanding Sages as times inherently infused with the quality of salvation – portals in time through which this influence would flow throughout the generations. They were thus ordained as holidays.
Therefore when we praise G‑d during Chanuka and Purim, “Who made miracles for our forefathers in those days at this time”, that is to say, the light of His miraculous salvation shines for us during these festivals even at this time!
This presents an explanation as to why, despite emphasizing that the miracles were wrought in those days, the festival of Chanuka was ordained not then, but only the following year (Shabbat 21b). At that time prophecy no longer existed and the Sages of the generation were unable to discern if the salvation was inherent to that time and eternal, or only temporary. When they saw the following year that these days emanated the light of salvation as during the previous one, they fixed them as days for “reciting praise and thanksgiving for every generation”!