Why Should We Kill Lizards in Islam?
Question

Why are we instructed to kill the Wazagh [a type of lizard], even though the Wazagh that exists now is not the one that breathed fire onto Ibrahim (peace be upon him), and it is known that no bearer of burdens will bear the burden [of sin] of another? Does the hadith which speaks of killing the Wazagh include the Wazagh lizards that are found in houses and those that are found in the wilderness and farms, because those that are found in the wilderness do not harm humans?
Praise be to Allah.Prophetic narrations on killing the Wazagh
It is commanded to kill the Wazagh, and the reason for that is that they are noxious little creatures [Fuwaysiq]. It is also commanded to kill other vermin, such as snakes, scorpions and vicious dogs.
Al-Bukhari (1831) narrated from `A’ishah – the wife of the Prophet (blessings and peace of Allah be upon him) – that the Messenger of Allah (blessings and peace of Allah be upon him) called the Wazagh a noxious little creature, but I did not hear him enjoin killing it.
Muslim (2238) narrated from Sa`d, from his father, that the Prophet (blessings and peace of Allah be upon him) enjoined killing the Wazagh and called it a noxious little creature. The reason why it is to be killed is that it is harmful.
Why should we kill lizards in Islam?
Ad-Dumayri said in Hayat Al-Haywan Al-Kubra (2/546): With regard to calling the Wazagh a noxious little creature [Fuwaysiq], it is similar to the five vermin [Al-Fawasiq Al-Khams] that may be killed both outside and within the Haram zone. The root meaning of Fisq [from which the word Fuwaysiq (noxious little creature) is derived] is to drift away, and these creatures have drifted away from the characteristics of most other similar animals, because they cause much greater harm. End quote.
Al-Bukhari (3359) narrated from Umm Sharik (may Allah be pleased with her) that the Messenger of Allah (blessings and peace of Allah be upon him) enjoined killing the Wazagh and said: “It used to blow on (the fire of) Ibrahim (peace be upon him).”
Al-Mulla `Ali Al-Qari (may Allah have mercy on him) said, commenting on this Hadith:
The Messenger of Allah (blessings and peace of Allah be upon him) enjoined killing the Wazagh lizard.
It is a small and harmful creature.
The Prophet (blessings and peace of Allah be upon him) said: “It used to blow on (the fire of) Ibrahim”; that is, the fire that was beneath him.
Al-Qadi (may Allah have mercy on him) said: This highlights the evil of this type of animal and the harm that it causes, as its evil reached such an extent that the devil used it and prompted it to blow into the fire into which Ibrahim (peace be upon him) was thrown, and it tried to make the fire flare up, so in general it is one of the venomous and harmful creatures.
Ibn Al-Malak (may Allah have mercy on him) said: It [the Wazagh] is very keen to spoil food, especially salt. If it finds no other way to spoil it, it climbs up to the ceiling and drops its faeces onto it. This hadith explains that its nature is to cause harm. (End quote from Mirqat Al-Mafatih, 7/2671).
The words “It used to blow on (the fire of) Ibrahim” indicate that it is innately evil and harmful, but that is not the only reason for killing it.
Ash-Shirwani (may Allah have mercy on him) [a Shafi`i scholar] said:
That is, because its ancestor was the one who blew onto the fire, which affirms the evil nature of this type of creature, by way of honouring Ibrahim. (End quote from Hashiyat Tuhfat Al-Muhtaj, 9/383).
Harmful nature of Wazagh
Among the harms of this creature that were mentioned by the scholars, it spits into vessels, as a result of which man is exposed to a great deal of harm, as is stated in `Umdat Al-Qari (15/250).
It is venomous and spits out venom, and it transmits serious diseases to those with whom it lives.
An-Nawawi (may Allah have mercy on him) said, explaining the reason for killing it: The scholars agreed that the Wazagh comes under the heading of harmful vermin.
The Prophet (blessings and peace of Allah be upon him) enjoined killing it, and urged and encouraged people to do so, because it is harmful. (End quote from Sharh Muslim, 14/236).
In conclusion, the Wazagh is not to be killed because of the sin of its ancestor; rather it is to be killed because it is harmful. Those that are found in houses and those that are found on farms are the same.
Rewards for killing the Wazagh
Regarding the reward for killing this noxious little creature, Muslim (2240) narrated that Abu Hurayrah said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Whoever kills a Wazagh with the first blow will have such and such rewards. Whoever kills it with the second blow will have such and such rewards, less than the first. Whoever kills it with the third blow will have such and such rewards, less than the second.”
And Allah knows best.