Proverbs 18:19 A brother offended is harder to be won than a strong city: and their contentions are like the bars of a castle.
Whether it be a brother or relative, or family member in YAHAWASHI HA MASHAYACH: we are able to hurt most those that we know best. In fact, it is because we know them best that it hurts the most.
This kind of wrong doing between family members is more easily seen as betrayal, because in many cases the hurt is coming from the same people who have been "on our side" other times in life. The thing is, we're all sinners. In every person there is a propensity to sin, and evil crouches at our doorstep waiting for the right moment to pounce.
Evil knows how deep these offences cut, and how dividing they can be without the power of forgiveness at work. The only way these relationships are restored after this kind of hurt is through forgiveness, always trusting in the Lord.