For on this day [Yom Kippur] He shall effect atonement for you to cleanse you. Before G‑d, you shall be cleansed from all your sins—Leviticus 16:30.

On Yom Kippur, G‑d mercifully erases all the sins we have committed "before G‑d"—but not the sins we may have committed against our fellow man. If we really want to come out of this holy day completely clean, we need to first approach any individual whom we may have wronged and beg their forgiveness. This applies whether the offense was physical, emotional, or financial (in which case, seeking forgiveness is in addition to making appropriate monetary restitution).

Just as the offending individual is enjoined to sincerely seek forgiveness, so, too, the victim is expected to wholeheartedly forgive—provided he is assured that the plea for forgiveness is indeed sincere.

More Details:

  • It is proper to specify the wrongdoing for which you are seeking forgiveness—unless doing so would cause further embarrassment to the victim.
  • If the injured party refuses to grant forgiveness, try approaching him several times, each time in the company of a few friends (who can try to convince the victim of the sincerity of your intentions).
  • If it is impossible to contact this person, make a firm resolution to ask forgiveness, with plans to do so when the opportunity arises. G‑d considers this resolution as if forgiveness was asked.
  • If the individual whom you have wronged has since passed away, and the gravesite is in the vicinity, take a minyan of ten adult men to the gravesite and beg forgiveness there. If the gravesite is not in the vicinity, you can appoint someone to go to the grave together with a minyan to ask for forgiveness on your behalf.