I killed a cat because it was harming the neighbors, and I ask about my punishment with God on the Day of Judgment and how to atone for this sin.

"If the cat you killed was causing harm beyond the norm, and people complained about its harm, then there is no blame upon you for killing it. A group of scholars have gone to the permissibility of killing a cat if it is of this description and it was not possible to repel it except by killing it. The conclusion is that if the cat was causing harm beyond the norm, and it was not possible to repel it with a light strike, or scolding, or removing it from the house, or the like, then it is permissible to kill it. The Hanafis are of the opinion that it should be slaughtered. As for if it was not causing significant harm, but rather was behaving as cats usually do, then it is not permissible to kill it. If it is killed, then the killer has sinned and is obligated to repent.

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