Leviticus 23:34
33 The Lord spoke to Moses: 34 “Tell the Israelites, ‘On the fifteenth day of this seventh month is the Feast of Shelters for seven days to the Lord. 35 On the first day is a holy assembly; you must do no regular work. 36 For seven days you must present a gift to the Lord. On the eighth day there is to be a holy assembly for you, and you must present a gift to the Lord. It is a solemn assembly day; you must not do any regular work.
Jubilees 16:21
19 And we went our way, and we announced to Sarah all that we had told him, and they both rejoiced with exceeding great joy. 20 And he built there an altar to the Lord who had delivered him, and who was making him rejoice in the land of his sojourning, and he celebrated a festival of joy in this month seven days, near the altar which he had built at the Well of the Oath. 21 And he built booths for himself and for his servants on this festival, and he was the first to celebrate the feast of tabernacles on the earth. 22 And during these seven days he brought each day to the altar a burnt offering to the Lord, two oxen, two rams, seven sheep, one he-goat, for a sin offering, that he might atone thereby for himself and for his seed.
Notes and References
"... the author was so bold as to assert that the very reason for the existence of these holy days was to be found not in the divinely-given prescriptions of the Sinai covenant, but in the events of the patriarchs’ own lives. That is to say, God did not command Abraham to celebrate the Festival of Booths (Sukkot); on the contrary, such-and-such a thing happened in Abraham’s life, and as a result he inaugurated the celebration of this festival on his own initiative (Jubilees 16:5-27). Only later did God tell Moses to promulgate a law in the Torah (Leviticus 23:33-35) commanding Israelites to celebrate the festival that Abraham had initiated, and to celebrate it on the precise date that Abraham had chosen for it ..."
Kugel, James L. A Walk through Jubilees: Studies in the Book of Jubilees and the World of Its Creation (p. 8) Brill, 2012