Does the hadith: "Whoever keeps a dog, his good deeds will decrease every day by one qirat, except for a dog of cultivation or livestock," apply to one who buys guard dogs for trade and breeding purposes without needing them for guarding?

The basic principle is that the Sunnah has emphasized strictness regarding the keeping of dogs without need. Therefore, it is not permissible to keep them except for a hunting dog, or for livestock, or for crops, or for guarding houses according to some Shafi'i scholars.

Raising a young puppy is permissible if it is for a lawful purpose, such as hunting or guarding, until it is trained. However, raising small dogs for sale is not included in the concession.

Selling dogs is absolutely forbidden according to the majority of scholars, even if they are among those whose keeping is permissible. The permissibility of selling them does not necessitate the permissibility of raising puppies for sale, especially in homes. Therefore, one should refrain from raising dogs for sale, in order to avoid the warning mentioned regarding the keeping of dogs.