It is a natural state of human beings to want to harm those who do no harm. An effect of action and reaction that is programmed in our genes to act instinctively, however, that becomes an endless battle, in marriage for example, always couples argue each other claiming that they are right, If person A takes damage from person B, A will want to return the damage to B, then B will be taking damage from A so he will want to return it, then it can become an infinite cycle of destruction. What the word says is that we must break that cycle, because God gave us the Holy Spirit so that we can tame our humanity. It's difficult but when you finally do well to other people they will usually reward you and that's much better.