Allah, He would fulfill it for them." [Agreed upon]. The Muslims have reached consensus on the implementation of retaliation in cases below the level of life if it is possible, and because [a part] below the level of life is like the life itself in the need to protect it through retaliation; therefore, it is like the life in the obligation of this [protection].

Section: Three conditions are required for the obligation of retaliation in wounds: First, that it be intentional (amdan mahdan). As for error, there is no retaliation for it by consensus, and because error does not necessitate retaliation in the case of a life—which is the original principle—so it is more appropriate that it does not do so in cases below it. It is not obligated for intentional error (amd al-khata'), which is when one intends to strike him with something that generally does not lead to that, such as striking him with a pebble that typically does not cause a clear wound, but it does cause one; retaliation is not obligated by this because it is quasi-intentional, and retaliation is not obligated except for purely intentional acts. Abu Bakr said: Retaliation is obligated by it, and it does not take that [distinction] into account, due to the generality of the verse. Second, equality between the perpetrator and the victim; this is that the perpetrator would be subject to retaliation from the victim if he had killed him, such as a free Muslim with another free Muslim. As for one who is not killed for killing him, then there is no retaliation from him in cases below the level of life, such as a Muslim with a disbeliever, a free person with a slave, or a father with his child; because his life would not be taken for his life, so his limb is not taken for his limb, nor is he wounded for his wound, like a Muslim with a person granted safety (musta'man). Third, the possibility of carrying out the retaliation without injustice or excess; because Allah the Almighty said: {And if you punish [an enemy, O believers], punish with an equivalent of that with which you were harmed} [Al-Nahl: 126]. And He said: {So whoever has assaulted you, then assault him in the same way that he has assaulted you} [Al-Baqarah: 194].