Chapter 16Gen. 19 describes how the progenitors of the nations of Ammon and Moab were the result of the incest of their mothers with their own father. Deuteronomy makes clear that the Israelites are not to hold this against these nations:
And when you come nigh over against the children of Ammon, distress them not, nor meddle with them: for I will not give you of the land of the children of Ammon any possession; because I have given it unto the children of Lot for a possession.Despite this, and despite the Toraitic injunction against punishing children for the sins of their parents, Jubilees takes a less accommodating stance, though deferring punishment until the end of days:
Behold, it was commanded and engraven concerning all [Lot's] seed, on the heavenly tablets, to remove them and root them out, and to execute judgment upon them like the judgment of Sodom, and to leave no seed of the man on earth on the day of condemnation.Jubilees finds precedent for the celebration of in the life of Abraham, after the angel has announced to Abraham and Sarah that, as well as Sarah being pregnant, Abraham would have six more children:
we went our way, and we announced to Sarah all that we had told him, and they both rejoiced with exceeding great joy. 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. 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. During these seven days he brought each day to the altar [snip details of offerings and incense, and more]. He blessed his Creator who had created him [...] for He knew and perceived that from him would arise the plant of righteousness for the eternal generations, and from him a holy seed, so that it should become like Him who had made all things. [...] For this reason it is ordained on the heavenly tablets concerning Israel, that they shall celebrate the feast of tabernacles seven days with joy, in the seventh month, acceptable before the Lord—a statute for ever throughout their generations every year. And to this there is no limit of days; for it is ordained for ever regarding Israel that they should celebrate it and dwell in booths, and set wreaths upon their heads, and take leafy boughs, and willows from the brook. And Abraham took branches of palm trees, and the fruit of goodly trees, and every day going round the altar with the branches seven times [a day] in the morning, he praised and gave thanks to his God for all things in joy.(Wreaths upon their heads?) Whilst there is no derivation of the festivals from the lives of the Patriarchs in the Bible, the rabbis would, a few centuries after Jubilees was written, declare that the lives of the Patriarchs were a sign for what would happen to their descendants.
Chapter 17Why did God test Abraham with the Binding of Isaac? Jubilees makes it at the instigation of Mastema, similar to God's testing of Job:
It came to pass in the seventh week, in its first year, in the first month in this jubilee, on the twelfth of this month, there were voices in heaven regarding Abraham, that he was faithful in all that He told him, and that he loved the Lord, and that in every affliction he was faithful. Then the prince Mastema came and said before God, 'Behold, Abraham loves Isaac his son, and he delights in him above all things else; bid him offer him as a burnt-offering on the altar, and You will see if he will do this command, and You will know if he is faithful in everything in which You test him.' The Lord knew that Abraham was faithful in all his afflictions; for He had tried him through his country and with famine, and had tried him with the wealth of kings, and had tried him again through his wife, when she was torn (from him), and with circumcision; and had tried him through Ishmael and Hagar, his maid-servant, when he sent them away. And in everything wherein He had tried him, he was found faithful, and his soul was not impatient, and he was not slow to act; for he was faithful and a lover of the Lord.
Chapter 18The Binding of Isaac story finishes in Jubilees with:
Abraham went to his young men; they arose and went together to Beersheba, and Abraham dwelt by the Well of the Oath. He celebrated this festival every year, seven days with joy, and he called it the festival of the Lord according to the seven days during which he went and returned in peace. And accordingly has it been ordained and written on the heavenly tablets regarding Israel and its seed that they should observe this festival seven days with the joy of festival.So that's a justification for from the lives of the Patriarchs too, though a week one, and a wholly unnecessary one too IMO in the light of its justification based upon the Exodus.