Book of Jubilees 6:18–29

¹⁸ And this whole festival was celebrated in heaven from the day of creation till the days of Noah -twenty-six jubilees and five weeks of years [1309-1659 A.M.]: and Noah and his sons observed it for seven jubilees and one week of years, till the day of Noah's death, and from the day of Noah's death his sons did away with (it) until the days of Abraham, and they eat blood. (JUB) ¹⁹ But Abraham observed it, and Isaac and Jacob and his children observed it up to thy days, and in thy days the children of Israel forgot it until ye celebrated it anew on this mountain. (JUB) ²⁰ And do thou command the children of Israel to observe this festival in all their generations for a commandment unto them: one day in the year in this month they shall celebrate the festival. (JUB) ²¹ For it is the feast of weeks and the feast of first fruits: this feast is twofold and of a double nature: according to what is written and engraven concerning it, celebrate it. (JUB) ²² For I have written in the book of the first law, in that which I have written for thee, that thou shouldst celebrate it in its season, one day in the year, and I explained to thee its sacrifices that the children of Israel should remember and should celebrate it throughout their generations in this month, one day in every year. (JUB) ²³ And on the new moon of the first month, and on the new moon of the fourth month, and on the new moon of the seventh month, and on the new moon of the tenth month are the days of remembrance, and the days of the seasons in the four divisions of the year. These are written and ordained as a testimony for ever. (JUB) ²⁴ And Noah ordained them for himself as feasts for the generations for ever, so that they have become thereby a memorial unto him. (JUB) ²⁵ And on the new moon of the first month he was bidden to make for himself an ark, and on that (day) the earth became dry and he opened (the ark) and saw the earth. (JUB) ²⁶ And on the new moon of the fourth month the mouths of the depths of the abyss beneath were closed. And on the new moon of the seventh month all the mouths of the abysses of the earth were opened, and the waters began to descend into them. (JUB) ²⁷ And on the new moon of the tenth month the tops of the mountains were seen, and Noah was glad. (JUB) ²⁸ And on this account he ordained them for himself as feasts for a memorial for ever, and thus are they ordained. (JUB) ²⁹ And they placed them on the heavenly tablets, each had thirteen weeks; from one to another (passed) their memorial, from the first to the second, and from the second to the third, and from the third to the fourth. (JUB)