(1) There was no water in it. The pit was twenty cubits deep, so they could not see that it was filled with snakes. That is why his miraculous survival did not cause them to repent.

Rabbi Yehuda says: If the flax was set on fire by the storekeeper’s Hanukkah lamp that he placed outside the entrance to his store, he is not liable, as in that case, it is permitted for the storekeeper to place his lamp outside. Ravina said in the name of Rabba: That is to say that it is a mitzva to place the Hanukkah lamp within ten handbreadths of the ground. As if it should enter your mind to say that he may place it above ten handbreadths, why is the storekeeper exempt? Let the camel owner say to the storekeeper: You should have placed the lamp above the height of a camel and its rider, and then no damage would have been caused. By failing to do so, the storekeeper caused the damage, and the camel owner should not be liable. The Gemara rejects this: And perhaps one is also permitted to place the Hanukkah lamp above ten handbreadths, and the reason Rabbi Yehuda exempted the storekeeper was due to concern for the observance of the mitzva of kindling Hanukkah lights. He held that if you burden one excessively, he will come to refrain from performing the mitzva of kindling Hanukkah lights. Since the storekeeper placed the Hanukkah lamp outside at the behest of the Sages, the storekeeper should not be required to take extra precautions. With regard to the essence of the matter Rav Kahana said that Rav Natan bar Manyumi taught in the name of Rabbi Tanḥum: A Hanukkah lamp that one placed above twenty cubits is invalid, just as a sukka whose roofing is more than twenty cubits high, and just as an alleyway whose beam, its symbolic fourth partition in order to place an eiruv, is more than twenty cubits high, are invalid. The reason is the same in all three cases: People do not usually raise their heads and see objects at a height above twenty cubits. As there is a requirement to see all of these, they are deemed invalid when placed above that height. And the Gemara cites another statement that Rav Kahana said that Rav Natan bar Manyumi taught in the name of Rav Tanḥum: What is the meaning of the verse that is written with regard to Joseph: “And they took him, and cast him into the pit; and the pit was empty, there was no water in it” (Genesis 37:24)? By inference from that which is stated: And the pit was empty, don’t I know that there was no water in it? Rather, why does the verse say: There was no water in it? The verse comes to emphasize and teach that there was no water in it, but there were snakes and scorpions in it.