Is hatred considered a person’s demanding their right from someone who wronged them in the Hereafter after having forgiven them in this world? And does forgiveness necessitate pardoning in this world and the Hereafter, or only in this world?

A sound heart is one that is free from desires that contradict Allah's commands and prohibitions, and from doubts that oppose His revelations. Part of its soundness from desires is its freedom from malice, rancor, arrogance, and conceit. Malice is the harboring of enmity in the heart, and it is blameworthy unless it has a legitimate reason, such as when an oppressed person harbors resentment towards their oppressor. In this case, they are entitled to lie in wait to claim their right, in fulfillment of Allah's saying: "Allah does not like the public utterance of evil, except by one who has been wronged" (An-Nisa: 148). Allah has permitted the oppressed to seek redress from those who wronged them: "The recompense for an evil deed is an evil deed like it" (Ash-Shura: 40). Forgiveness in this world means the oppressed person relinquishing their right, so there will be no consequence for the oppressor in the Hereafter.