What do Purim and Yom Kippur have in common?
What they have in common is being the extremes.
On the one hand, we have Yom Kippur, the time of absolute Transcendence, the most dense presence that rips through all Reality, the only day of the year when the High Priest utters the sacred name of God in the Holy of Holies.
On the other hand, we have Purim, a festival of natural events, with not even the slightest mention of holiness, without even the name of God being mentioned.
The high and the low meet.
There are only two extreme situations: one where we must take everything into account and the other, the time of forgiveness, which is above all accounts.
Absolute transcendence meets absolute immanence.
–Rabbi Adin Steinsaltz
From Seven Lights by Rabbi Adin Steinsaltz