Muslim

Hadith Commentary:

From this hadith, it is understood that it is permissible to keep a dog for the protection of crops, just as it is permissible to keep a dog for hunting.
Keeping a dog merely for amusement is prohibited, because it entails many dangers.
The greatest danger is that such dogs, whenever they get the chance, put their mouths into vessels and keep contaminating them.
They also trouble those who come and go.
There is a fear of their biting.
For this reason, the angels of mercy do not enter a house in which this harmful animal is kept.
The good deeds of a Muslim who keeps a dog without benefit are diminished by one qirat each day.
Hafiz (rahimahullah) says:
“In these ahadith is the virtue of planting and the virtue of cultivation, and that the reward for the one who does this continues as long as the plants and crops and what is produced from them remain, until the Day of Resurrection. The scholars have differed regarding the best and purest means of earning a livelihood: it is said trade, it is said craftsmanship by hand, and it is said agriculture—and this is correct. I have elaborated on this at the end of the chapter on foods in the commentary of al-Muhadhdhab. In these ahadith also is that reward and recompense in the Hereafter is specific to the Muslims, and that a person is rewarded for what is stolen from his wealth or what is destroyed by an animal or a bird or the like, etc.”
And in the hadith is encouragement to increase righteous deeds and a warning against actions that diminish them, and a reminder of the causes of increase and decrease in them, so that they may be avoided or undertaken, and a clarification of Allah’s kindness to His creation in permitting for them that which is beneficial, and the conveying by their Prophet (sallallahu alayhi wa sallam) of matters relating to their livelihood and their Hereafter. And in it is the preference of the preponderant benefit over harm, as is evident from the exception of what is beneficial from what is prohibited to keep (Fath al-Bari).

That is, one reason for the reduction of a qirat from good deeds is that the angels of mercy do not enter such a house, or that because of the dog, those who come and go are troubled.
Or it may be because some dogs are devils, or because despite the prohibition, the dog is kept, thus good deeds are diminished, or because they keep putting their mouths into vessels.
Whenever the household is a little negligent, the dog immediately contaminates pure water.
Now, if that is used for worship, purity will not be attained from it.
In short, these are all the reasons due to which the good deeds of those who keep dogs merely for amusement are diminished by one qirat each day.
But, alas for Western civilization! Nowadays, in this new culture, keeping dogs has also become a fashion.
In wealthy households, such dogs kept merely for amusement are served to such an extent that there are special servants for bathing and cleaning them.
Special arrangements are made for their food.
Astaghfirullah! Muslims must, in any case, avoid such useless and wasteful extravagance.
Hafiz (rahimahullah) says that this hadith contains many benefits, among which is encouragement to increase righteous deeds, and also a warning against such evil deeds that destroy good deeds and incur sin.
In this hadith, there is a reminder for both matters: that good deeds should be done in abundance and evil deeds should be avoided in abundance.
And also that Allah’s kindness to His creation is such that whatever is beneficial for them has been made permissible, and in this hadith, the prophetic conveyance regarding matters of livelihood and the Hereafter is also mentioned.
And from this hadith, it is also evident that some things are prohibited, such as keeping a dog, but in cases where there is benefit, they are made exceptions due to necessity.

Hadith Commentary:

Dogs certainly, at some point, cause some kind of harm to someone; for this harm, the owner who keeps them will be held responsible. The dogs that are kept for protection will necessarily be under the owner's control; therefore, they have been exempted.

Benefits and Issues:
Apart from these purposes, keeping a dog is a sin and a matter of loss.
For every day, one qirat is deducted from his reward.
And Allah knows what the weight of this will be.
Whereas in weights, a qirat is referred to as the weight of 2125 grams of silver.

Benefits and Issues:
➊
The punishment for committing a prohibited act can also be that the reward for previously performed good deeds is lost.

➋
A qirat is a small unit of weight, which is equal to one mashiyah or even less, whereas the Prophet (sallallahu alayhi wa sallam), in encouraging participation in funeral prayers, described its amount as being equal to Mount Uhud. Regarding what is meant by the qirat mentioned in this hadith, there is no clarification from the Messenger of Allah (sallallahu alayhi wa sallam); therefore, any amount of weight may be intended by it. For a Muslim, it is a matter of regret and remorse that daily, from his reward, an amount equal to Mount Uhud or the well-known weight of a qirat is reduced. And Allah knows best.

Takhrij:
«أخرجه البخاري، الحرث والمزارعة، باب إقتناء الكلب للحرث، حديث:2322، ومسلم، المساقاة، باب الأمر بقتل الكلاب...، حديث:1575.»©Explanation:
➊ From the aforementioned hadith, it is understood that keeping a dog for amusement of the heart or fulfillment of idle desires is prohibited; however, it is permitted to keep a dog for hunting, agriculture, or for the care of livestock and similar purposes.
For any purpose other than these, keeping a dog results in a daily reduction of one qirat of reward.
➋ Qirat is a small unit of weight, which is equivalent to one masha or even less, whereas the Noble Prophet (sallallahu alayhi wa sallam), in encouraging participation in funeral prayers, described its amount as equal to Mount Uhud.
What is meant by qirat in this hadith? There is no clarification from the Messenger of Allah (sallallahu alayhi wa sallam) regarding this; therefore, whether it refers to any weight, it is a matter of regret and remorse for a Muslim that daily, from his reward, an amount equal to Mount Uhud or the well-known weight of one qirat is reduced.
And Allah knows best.