"Bear with each other and forgive whatever grievances you may have against one another. Forgive as the Lord forgave you" (Colossians 3:13).
In his remarkable book, The Sermon on the Mount, Dr. Emmet Fox deals with our forgiving those who hurt us. In the chapter, "Resist Not Evil", he states, "...When someone injures you, instead of seeking to get your own back or to repay him in his own coin, you are to do the very opposite--you are to forgive him, and set him free. No matter what the provocation may be, and no matter how many times it is repeated, you are to do this. You are to loose him and let him go, for thus only can you be freed yourself--thus only can you possess your own soul. To return evil for evil, to answer violence with violence and hate with hate, is to start a vicious circle to which there is no ending but the wearing out of your own life and your brother's, too. Antagonize any situation, and you give it power against yourself; offer mental non-resistance, and it crumbles away in front of you."
Dr. Fox points out that "the mere rehearsing in thought of any difficulty endows it with new life. Going over old grievances mentally; thinking how badly someone acted at some time, for instance, and recalling the details, has the effect of revivifying that which was quietly expiring of neglect."
By mentally resisting what we feel is a bad circumstance, we give it power and life and, in the process, deplete our own spiritual energies and, perhaps, even our physical stamina. Resentment fosters self-pity which fosters inability to act and react in a Christ-like way. In our anger and frustration, we also are tempted to give others "a piece of our mind" and, in the process, lose our own peace of mind.
Years ago a friend gave me some wonderful advice. She suggested that I visualize Jesus standing between the person and myself, and imagine Him absorbing and redeeming the feelings of anger I had toward that person. It works! Another help, I would picture myself washing the feet of that person, as Christ washed the feet of Judas, His betrayer.