Hoshana Rabba, the culmination of Sukkos, is a day of deep spiritual significance, marking the final seal on the judgments of Yom Kippur. It is a day of heartfelt tefillos and an opportunity to sweeten dinim (judgments) through increased ahavas Yisroel and tzedakah. This is why Chassidim traditionally increase their giving on this day. As the Rebbe expressed during the farbrengen of Hoshana Rabba 5744 (1983):
“ביום זה שענינו מיתוק הגבורות יש להוסיף בצדקה יותר מהרגילות.”
(On this day, whose essence is the sweetening of judgment, one should increase in tzedakah beyond the usual.)