‘that a life for a life,’ meaning: the life that killed [in retaliation] for the life that was killed. And this is [concerning free persons].

His saying, the Almighty: {But if the killer is forgiven by the brother of the slain, then there should be a pursuit of him with fairness and an honest payment to him.} The interpretation of Qatadah: He says: Whoever kills intentionally, and is forgiven, and the blood money is accepted from him, {then there should be a pursuit with fairness and an honest payment to him} [the one pursuing is commanded] to pursue with fairness, [and the one paying is commanded] to pay with kindness. {That is a concession from your Lord and a mercy.} Qatadah said: The people of the Torah were commanded [to apply] the fixed legal punishments (Hudud), and the people of the Gospel were commanded to grant pardon. This nation was given the choice of retaliation, pardon, or blood money; if they wish, they may kill; if they wish, they may pardon; and if they wish, they may take the blood money, provided they mutually agree upon it. {And a mercy} means: Allah showed mercy to this nation through it, and He allowed them [to accept] blood money. Qatadah said: It was not [permitted] for anyone before them in cases of intentional killing. {Then whoever transgresses after that,} meaning: against the killer by killing him after accepting the blood money from him, {then for him is a painful punishment,} meaning: the ruler shall execute him, and no consideration shall be given in that matter to the pardon of the guardian of the slain.