Mark, on the fifteenth day of the seventh month, when you have gathered in the yield of your land, you shall observe the festival of Hashem to last seven days. LEVITICUS 23:39 (The Israel Bible™)
The seventh feast given to Israel is called Sukkot (Feast of Tabernacles). After the Children of Israel entered the Holy Land, Sukkot became the festival associated with the fall harvest during which thanks was given to Hashem for sustaining the Children of Israel with the bounty of the Land. In fact, the Torah refers to the Feast of Tabernacles both as Chag HaSukkot and Chag HaAsif, the festival of booths and the harvest festival. In emulating Hashem’s care and generosity toward His people, Sukkot is an important time to give charity in general, and especially to the Land and People of Israel.