What is the ruling concerning a person who killed a mouse while he was standing on ‘Arafah?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

It is permissible in the Islamic Sharee'ah for a person in a state of ihram (ritual consecration) to kill such things that usually harm people, like snakes, scorpions, mice, crows, and biting dogs. This is related in a Hadeeth on the authority of ‘Aa'ishah who related the following: "The Prophet, sallallaahu ‘alayhi wa sallam, commanded us to kill five fawasiq (wicked beasts) in the state of ihram or otherwise: crows, kites, scorpions, mice, and biting dogs." [Al-Bukhari]

The Prophet, sallallaahu ‘alayhi wa sallam, called these five as fawasiq. Al-Munawy reported from Az-Zamakhshari that fisq, here, means maliciousness and violation of the place' sanctity. He reported from others that they are fawasiq in the sense that as they do harm and cause corruption, they act differently from most other beasts. It is as if their fisq in this meaning was a reason that permitted killing them, given their harm. Hence, there is nothing due on a person who kills a mouse while he is standing on ‘Arafah.

Allaah Knows best.