Noah in rabbinic literature "Sefer haYashar" describes another method for distinguishing them: the clean animals and fowls crouched before Noah, while the unclean ones remained standing. A difference of opinion concerning Noah prevails also with regard to his entering into the ark. According to some rabbis, Noah's faith was so small that he did not enter the ark until he stood ankle deep in water (Genesis Rabba xxxii. 9); others declare, on the contrary, that Noah waited for God's directions to enter the ark, just as he awaited His permission to leave it (ib. 34.4; Midrash Agadat Bereshit, in Jellinek, "B. H." iv. 11).
Book of Noah compounded of the Semjaza and Azazel myths, and in its present composite form is already presupposed by 1 Enoch 88-90. Hence these chapters are earlier than 166 B.C. Chapters 106-107 of the same book are probably from the same source; likewise 54:7-55:2, and Jubilees 7:20-39, 10:1-15. In the former passage of Jubilees the subject-matter leads to this identification, as well as the fact that Noah is represented as speaking in the first person, although throughout Jubilees it is the angel that speaks. Possibly Eth. En. 41:3-8, 43-49, 59 are from the same work. The book may have opened with Eth.