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).
Noah's Ark been no need to distinguish between clean and unclean animals before this time, the clean animals made themselves known by kneeling before Noah as they entered the ark. A differing opinion said that the ark itself distinguished clean animals from unclean, admitting seven pairs each of the former and one pair each of the latter. According to Sanhedrin 108b, Noah was engaged both day and night in feeding and caring for the animals, and did not sleep for the entire year aboard the ark. The animals were the best of their species, and so behaved with utmost goodness. They abstained