Yom Kippur (the Day of Atonement) is unlike any other day in the calendar — and according to Tanna DeBei Eliyahu Rabbah, a midrash (rabbinic interpretive commentary)ic work traditionally attributed to the prophet Elijah and compiled around the 10th century CE, the Psalmist already knew this. The verse "These days were formed, but not one from them" (Psalms 139:16) is interpreted as referring specifically to Yom Kippur.
The Hebrew is cryptic, and that is precisely the point. "These days were formed" — all the days of the year were created, each one assigned its purpose in the cosmic order. "But not one from them" — Yom Kippur stands apart. It was formed alongside the other days, yet it belongs to a different category entirely. It is a day that exists outside ordinary time.
Every other day of the Jewish year operates within the normal rhythms of creation: work and rest, planting and harvest, celebration and mourning. Yom Kippur suspends all of it. For twenty-five hours, the nation of Israel is lifted out of the material world. No eating, no drinking, no leather shoes, no bathing, no anointing with oil. The body is stripped down to its spiritual minimum.
The midrash suggests this was always the plan. When God designed the calendar, He built in one day that would function differently from every other — a day when the boundary between human and angel would thin, when mortals could stand before the divine throne and have their sins erased. The Psalmist, gazing at the full span of creation, noticed this anomaly and recorded it: all these days were shaped and set in place, but one of them does not belong to the ordinary count. One of them was made for something else entirely.