The 10 commandments are laws of love,to love God and love people,which can apply to more than that,which the Bible says love works no harm towards their neighbor,therefore love is the fulfilling of the law.
Loving God and loving people are the 2 greatest commandments,to not offend God and not offend people in any way,which is true love,which is the fulfilling of the law.
The 10 commandments include laws to not offend people in their basic form,which sets a base to know not to offend your neighbor in anything,that does not need to be specifically included in the 10 commandments.With the 10 commandments that are laws to not offend God and not offend people,it becomes common sense not to offend God and people in all areas.
If everybody obeyed the 10 commandments,and truly loved one another,in which love does not offend their neighbor in any way,then what would there be to forgive.To follow the 10 commandments obeyed by everyone,we would not have to forgive anyone,for nobody would offend.
The 10 commandments are laws of love that cover not offending God and not offending people only,and forgiveness is not a law of not offending a person,but an act of someone offending you and you dismissing it by forgiving that person.Forgiveness is not a law of you not offending people,so it is not included in the 10 commandments.