Vayikra 23:33-35

Orthodox Jewish Bible

³³ And Hashem spoke unto Moshe, saying,

³⁴ Speak unto the Bnei Yisroel, saying, The fifteenth day of this seventh month shall be the Chag HaSukkot for shivat yamim unto Hashem.

³⁵ On the Yom HaRishon shall be a mikra kodesh; ye shall do no melekhet avodah (laborious work) therein.