Bukhari

Hadith Commentary:
The absolute mujtahid, Hazrat Imam Bukhari rahimahullah, has derived from this hadith the ruling that it is permissible to dig a well on the road so that passersby may drink from it and benefit from its comfort, provided there is no fear of harm; otherwise, the one who digs it will be held liable. It is also evident that giving water to every living being—whether human or animal, disbeliever or Muslim—is a great act of reward.
Even a dog has the right that if it is thirsty, it should also be given water.

Hadith Commentary:
(1)
The purpose of this heading is not that a well should be dug right in the middle of the road, but rather that it should be on either side of the road. At that time, for the service of creation, unlined wells were constructed on the edges of pathways. These wells also had steps for descending into them.

(2)
From this, it is understood that a well can be constructed along a pathway so that travelers passing by may drink from it and quench their thirst, provided that it does not cause harm or inconvenience to anyone.

(3)
This hadith also shows that providing water to every living being—whether human or animal, Muslim or non-Muslim—is a highly meritorious act. Even a dog has the right that if it is thirsty, it should also be given water.

Hadith Commentary:

It is a manifestation of Allah’s mercy that merely by giving water to a dog, that person became deserving of forgiveness. This is why it has been said that one should not consider even a small good deed to be insignificant; one does not know through which act of goodness Allah, the Exalted, may become pleased and forgive all sins.

Hadith Commentary:
(1)
A similar incident is also narrated in Sahih al-Bukhari regarding an immoral woman from the Children of Israel; Allah Almighty forgave her due to this act of service.
(Sahih al-Bukhari, Ahadith al-Anbiya, Hadith: 3467)
It is possible that there were multiple such incidents.

(2)
This is a manifestation of Allah Almighty’s mercy, that simply by giving water to a thirsty dog, a person became deserving of forgiveness. Therefore, a person should not consider any good deed insignificant or trivial.
Who knows, perhaps Allah Almighty may like that deed and, in return, grant forgiveness.
In any case, we should maintain a gentle attitude towards animals.
We should treat them with mercy and kindness when making use of them.
And Allah knows best.

Hadith Commentary:
It is established that giving water to any living being and thus quenching its thirst is such an act that can become a cause for forgiveness.
Just as this person gave water to a thirsty dog, and due to this very act, he was forgiven.
The Maulana states that this is apparently general and includes every animal; some have said that what is meant by this are lawful (halal) domesticated animals.
And that there is no reward in (giving water to) dogs, pigs, etc., because there is an order to kill them. I (Maulana Waheed al-Zaman)
say that it is better to keep the hadith unrestricted (mutlaq).
As for dogs and pigs, is it necessary that they be killed while thirsty?
First, give them water, and then kill them.
Abu ‘Abd al-Malik said that this hadith pertains to the people of Bani Isra’il.
They were not ordered to kill dogs.
(Waheedi)
In the hadith, the phrase “in every moist liver” is general, which includes every living being; in this respect, the explanation of Maulana Waheed al-Zaman rahimahullah is excellent.

Hadith Commentary:
(1)
In another narration of Sahih al-Bukhari it is stated:
"Allah, having accepted his good deed, admitted him into Paradise."
(Sahih al-Bukhari, al-Wudu, Hadith: 173)

(2)
From this hadith, it is understood that one should show compassion and kindness to living creatures, and there is great virtue especially in doing good to people, because if giving water to a thirsty dog becomes a cause for forgiveness, then one should hope for immense reward in serving human beings. This also indicates the virtue of giving water, showing how much value and status this act holds with Allah.
(Fath al-Bari: 5/53)

Hadith Commentary: Benefits and Issues: This hadith establishes that showing compassion and goodwill towards every living being, and fulfilling its natural needs, is a source of reward. Provided that the animal is not harmful or injurious.

Benefits and Issues:
➊ Arranging water for people in inns and along their paths is a very great act of virtue.

➋ Doing good to a human being, whether Muslim or non-Muslim, as well as to other living creatures, is a matter of great reward. However, those animals that are to be killed (wajib al-qatl) and harmful creatures are exempt from this kindness, such as the pig, snake, scorpion, etc.