To apologise (khamati) is to express one's recognition of and sorrow for having hurt another. Sometimes we break one or another of the Precepts in a way that hurts or offends others. One way we can make amends for this is to express our contrition to the person we have hurt. Giving a sincere apology, without reservation or self-justification, is one of the higher forms of generosity. By doing so we help heal any anger or resentment the other person may feel, we ease the way for them to practise forgiveness and we make possible the mending of a ruptured relationship. On our part, giving a sincere, unreserved and timely apology soothes any self-reproach we might feel and helps us become more open about and objective towards the negative side of our character, which is an important part of character building.
If apologising can be difficult, it is also true that pardoning a transgression is just as difficult. This is why the Buddha said that it is incumbent on a person who has done wrong to apologize, just as it is incumbent on the person who has been wronged to accept an apology and then respond with forgiveness (Vin.I,54). The person who has done wrong has an obligation to make the first move and say he or she is sorry. After that, the person who has been wronged is obliged to accept the apology and then forgive.
There were several incidents where the Buddha said things that deeply upset people; proclaiming the truth sometimes involves breaking cherished idols. He never apologised for doing this because his concern was always the best interests of the person involved. For us though, with our imperfections, our ego and our lack of mindfulness, apologising is one way we can heal some of the hurt we may have caused.