Is it incumbent upon me to rid myself of the feeling of guilt and to repent if I am certain that I received a larger share when a piece of land was divided, given that I had no experience with such matters at the time, and given that it is now impossible to rectify the error?

Our view is that the questioner should seek forgiveness from his Lord and perform many good deeds, and be kind to the members of the other team to the best of his ability. This is out of precaution and to prepare for the Hereafter, and not because the other team has a fixed right against the questioner. The division occurred in a traditional manner with the presence of a representative from the other team, so the matter was akin to a reconciliation or a permissible amicable division, even if some suffered a disadvantage, as long as the disadvantaged party was an adult and of sound mind.