Are those who exchange acquittals considered sinful?

The wronged person does not sin if he retaliates against someone who cursed him or wronged him; rather, the one who initiated the transgression sins. The sin of both disputants falls upon the one who began, as long as the wronged person does not exceed the bounds in his retaliation. Allah the Almighty said: "The recompense of an evil deed is an evil deed like it. But whoever pardons and makes reconciliation – his reward is [due] from Allah. Indeed, He does not like wrongdoers. And whoever avenges himself after he has been wronged – those have not upon them any cause [for blame]. The cause [for blame] is only against those who wrong people and tyrannize upon the earth without right. Those will have a painful punishment. But whoever is patient and forgives – indeed, that is of the matters [requiring] determination" (Ash-Shura: 40-43). However, patience and forgiveness are better.

It is permissible for the cursed person to retaliate with the like of what he was cursed with, unless the curse was a lie, slander, or a curse against his ancestors; because lying and slander are forbidden. If he curses him, he may curse him in return. If he calls him an animal, he may respond in kind. However, if he curses his father, he is not permitted to curse his father, because his father did not wrong him.

Disowning some relatives from their kin is forbidden if it leads to cutting off ties of kinship or denying lineage, based on the saying of the Messenger of Allah, peace and blessings be upon him: "No cutter of kinship ties will enter Paradise." The advice is to fulfill rights, strive for reconciliation, maintain ties of kinship, and beware of severance.