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CHAPTER VIII 1 THE PRINCIPLE OF INTERCALATION - Pirke de Rabbi Eleazar
[9A. i.] On the 28th of Eilul the sun and the moon were created.2 The number of years, months, days, nights,3 terms, seasons, cycles, and intercalation were before the Holy One, blessed be He,4 and He intercalated the years and afterwards He delivered the (calculations) to the first man in the garden of Eden,5 as it is said, "This is the calculation"6 for the generations of Adam" (Gen. v. 1), the calculation of the world is therein for the generations of the children of Adam. Adam handed on the tradition to Enoch,7 who was initiated in the principle of intercalation, and he intercalated the year, as it is said, "And Enoch walked with God " (ibid. 22). Enoch walked in the ways of the calculation concerning the world which God had delivered to Adam. And Enoch delivered the principle of intercalation to Noah,8 and he was initiated in the principle of intercalation, and he intercalated the year…
Noah handed on the tradition to Shem, and he was initiated in the principle of intercalation; he intercalated the years and he was called a priest, as it is said, "And Melchizedek14 king of Salem . . . was a priest of God Most High" (ibid. xiv. 18).
Shem delivered the tradition to Abraham; he was initiated in the principle of intercalation and he intercalated the year… Abraham delivered the tradition to Isaac, and he was initiated in the principle of intercalation, and he intercalated the year after the death of our father Abraham, 18 Isaac gave to Jacob19 all the blessings and delivered to him the principle of intercalation. 21 Jacob delivered to Joseph and his brethren the principle of intercalation, and they intercalated the year in the land of Egypt. (When) Joseph and his brethren died, the intercalations ceased from Israel in Egypt, Just as the intercalations were diminished from the Israelites in the land22 of Egypt, likewise in the future will the intercalations be diminished at the end of the fourth kingdom23 until Elijah, be he remembered for good, shall come. 24 Just as the Holy One, blessed be He, was revealed to Moses and Aaron in Egypt, likewise in the future will He be revealed to them25 at the end of the fourth kingdom,26 as it is said, "And the Lord spake unto Moses and Aaron in the land of Egypt saying, 27 This month shall be unto you the beginning of months" (ibid. xii. 1, 2). Till now29 the principle of intercalation was with Me, henceforth it is your right to intercalate thereby the year.30 Thus were the Israelites wont to intercalate the year in the (Holy) Land.