Jubilees 16
1, "And at the first day of the fourth month we appeared to
Abraham...and we announced to him that a son would be given him from
Sarah his wife...
3 and told her that name of her son...Isaac...
11 And in the middle of the sixth month the Lord visited Sarah, and
did unto her as he said unto her, (Compare with Luke 1:26-31)...)
12 and we returned in the seventh month and found Sarah pregnant
before us, and we blessed her and told her all things that had been
commanded us concerning him (Abraham) that he should not die until
six sons had been born unto him...but that in Isaac his name and seed
should be called...
14 for he (Isaac) shall become the portion of the Most High, and
among those of whom God is ruler will be his abode and all his seed,
and it became a seed of the Lord, a nation of inheritance among all
nations, and that it may become a kingdom and a priesthood and a holy
nation.
15 And we went our way, and we announced to Sarah all that we had
told him; for these rejoiced with exceeding great joy."
And so:
19 "And thus he celebrated his festival seven days, rejoicing with
his whole heart and his whole soul, and he and all those that were in
his house, and there was not any stranger with him nor any bastard.
20 And he blessed his creator... (to Verse 23) on this account it
is ordained in the tablets of heaven concerning Israel that they shall
celebrate The Festival Of Tabernacles seven days in joy in the seventh
month...as an eternal law...
24 And to this there is no
limit of days, but it is ordained over Israel as a festival
that they shall observe it."