Chapter 44: The reconciliation of those excommunicated

Anyone who is excommunicated from the refectory only for a less serious fault should perform the same act of reparation in the oratory until permitted to cease; the superior brings this penance to an end by giving a blessing and saying 'that is enough'. (From para. 2 of Ch. 44 of Saint Benedict's Rule, trans. by Patrick Barry, OSB, 1997.)

I think the power behind the words "that is enough" is that of forgiveness and personal growth, when a time of sorrow must become a time of new life.