Why is it so hard to forgive? (Dr. Michelle Friedman)

It is forbidden for man to be ill-natured and unforgiving, for he must be easily appeased but unwidely to wrath; and when a sinner implores him for pardon, he should grant him pardon wholeheartedly and soulfully. Even if one persecuted him and sinned against him exceedingly he should not be vengeful and grudge-bearing, for such is the path of the seed of Israel and of their excellent heart. Only the idolaters are not so, they are of uncircumcised heart, and their wrath is ever-watchful; and, because the Gibonites were unforgiving and unappeasing…

To Reconcile with Your Friend on Erev Yom Kippur, 4 Seifim: Transgressions between people are not subject to atonement on Yom Kippur unless the offender appeases the offended party. Even if one aggrieved another with words alone, this appeasement is necessary. If one cannot effect appeasement at first, one must return a second and a third time, taking along three people each time. If the offended party will not be appeased after three visits, one may desist. RAMA: afterwards, however, the offender should relate before ten people that forgiveness was sought (Mordechai on Yoma…)