Sayyiduna Ibn Umar (may Allah be pleased with them both) says: I heard the Messenger of Allah (peace and blessings be upon him), he commanded to kill dogs and said: Kill snakes and dogs. And kill the snake with two lines (on its back) and the one with a short tail, for both of them cause blindness and make pregnant women miscarry. Zuhri said: Perhaps this effect is due to their venom. Salim said: Abdullah bin Umar (may Allah be pleased with them both) said: Whenever I see a snake, I immediately kill it. Once, I was chasing one of the house snakes when Zayd bin Khattab or Abu Lubabah (may Allah be pleased with him) passed by in front of me while I was chasing it. He said: O Abdullah, wait! I said: The Messenger of Allah (peace and blessings be upon him) has commanded to kill snakes. He said: The Messenger of Allah (peace and blessings be upon him) has forbidden killing house snakes. (That is, those snakes which are not venomous and live in houses, or sometimes live in the form of devils; killing them causes harm from other devils, which is explained in the next hadith in detail.)

Abu Sa’ib, the freed slave of Hisham bin Zuhrah, narrates that he went to Sayyiduna Abu Sa’id Khudri (may Allah be pleased with him) at his house. Abu Sa’ib said that he found him engaged in prayer, so he sat down. He waited for him to finish his prayer, and in the meantime, he heard a sound of movement from the wood that was placed in the corner of the house. He looked over and saw a snake. He rushed to kill it, but Sayyiduna Abu Sa’id (may Allah be pleased with him) gestured to him to sit down. He sat down, and when he finished his prayer, he showed him a small room and asked,“Do you see this room?”I said,“Yes.”He said,“A young man from among us used to live in it, who had recently gotten married. We went out with the Messenger of Allah (peace and blessings be upon him) towards the trench (Khandaq). That young man used to take permission from the Prophet (peace and blessings be upon him) at noon to come home. One day, he sought permission from the Prophet (peace and blessings be upon him), and the Prophet said, ‘Take your weapons with you, for I fear the Banu Qurayza (who had betrayed and, finding an opportunity, joined the polytheists).’ The man took his weapons. When he reached his house, he saw his wife standing between the two doors. Out of jealousy, he raised his spear to strike her, but the woman said, ‘Put your spear down and go inside to see why I have come out.’ The young man went inside and saw a large snake coiled up on the bedding. The young man raised his spear at it and pierced it with the spear, then came out and planted the spear in the ground. The snake attacked him. After that, we do not know whether the snake died first or the young man was martyred first. We came to the Messenger of Allah (peace and blessings be upon him) and narrated the whole story and said, ‘O Messenger of Allah! Pray to Allah to bring that young man back to life.’ The Prophet (peace and blessings be upon him) said, ‘Pray for forgiveness for your companion.’ Then he said, ‘There are jinn in Madinah who have become Muslims. So if you see snakes, warn them for three days. If they do not leave after three days, then kill them, for they are devils (i.e., disbelieving jinn or evil snakes).’

Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with them) says that we were with the Messenger of Allah (peace and blessings of Allah be upon him) in a cave when Surah "Wal-Mursalat 'Urfa" was revealed to him. We were listening to this Surah fresh from the blessed mouth of the Prophet (peace and blessings of Allah be upon him) when suddenly a snake appeared. The Prophet (peace and blessings of Allah be upon him) said: Kill it. We rushed to kill it, but it got ahead of us (i.e., it hid). The Prophet (peace and blessings of Allah be upon him) said: Allah Almighty saved it from your hands just as He saved you from its harm.

It is narrated from Sayyiduna Sa’d bin Abi Waqqas (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) ordered the killing of the gecko and called it“fawaysiq”(i.e., a small evildoer).

Sayyiduna Abu Hurairah (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) said: Whoever kills a gecko with the first strike, he will have such-and-such reward; whoever kills it with the second strike, he will have such-and-such reward, but less than the first; and whoever kills it with the third strike, he will have such-and-such reward, but less than the second. In another narration, the Noble Prophet (peace and blessings be upon him) said: Whoever kills a gecko with the first strike, one hundred good deeds will be written for him; whoever kills it with the second strike, he will have less than that; and whoever kills it with the third strike, he will have less than that.

Abu Huraira (may Allah be pleased with him) narrates from the Noble Prophet (peace and blessings be upon him) that he said: One of the prophets among the prophets stopped under a tree, and an ant bit him. So, by his order, the nest of the ants was taken out, and then he ordered it to be burned. Then Allah Almighty revealed to him: You could have punished the one ant (that bit you); what was the fault of the other ants?

Narrated from Abdullah bin Umar (may Allah be pleased with them) that the Messenger of Allah (peace and blessings of Allah be upon him) said: A woman was punished because of a cat. She kept the cat confined until it died, and because of that cat, she entered Hell. When she kept the cat imprisoned, she neither gave it food nor water, nor did she let it go so that it could eat the creatures of the earth. (She tortured the cat to death, and that is why she went to Hell.)

Sayyiduna Abu Hurairah (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) said: A group from the Children of Israel was lost, and it was not known what happened to them. I think that group became mice (by transformation). Do you not see that when camel milk is placed before mice, they do not drink it, but when goat milk is placed, they drink it? (The indication is that the mice are those people from the Children of Israel who were transformed, even if they did not remain alive, because in the Shariah of the Children of Israel, the meat and milk of camels were forbidden.) Sayyiduna Abu Hurairah (may Allah be pleased with him) said: I narrated this hadith to Sayyiduna Ka'b, so he asked, "Did you hear this from the Messenger of Allah (peace and blessings be upon him)?" I said, "Yes." He asked several times, so I said, "Do I read the Torah? (That I would have obtained this narration from it? All my knowledge is what I have heard from the Messenger of Allah, peace and blessings be upon him.)" In another narration, Sayyiduna Abu Hurairah (may Allah be pleased with him) replied, "Is the Torah revealed to me (that I would read it and tell you from it)?"

Narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: A man was walking on the road in a state of great thirst when he found a well. He went down into it and drank water. Then he came out and saw a dog that, due to thirst, was sticking out its tongue, panting, and licking wet soil. The man said, "This dog's condition from thirst is just like mine was." Then he went down into the well, filled his sock with water, held the sock in his mouth, climbed up, and gave the water to the dog to drink. So Allah Almighty accepted this good deed of his and forgave him. The people asked, "O Messenger of Allah! Is there a reward for us in feeding and giving water to animals as well?" He (peace and blessings be upon him) said, "There is a reward in (doing good to) every living being with a moist liver." (He said this because the body and liver of a dead animal become dry.)