Rejoicing in tribulation

In Martyn Lloyd-Jones book 'STUDIES IN THE SERMON ON THE MOUNT,' he states on the Rejoicing in Tribulation section--chapter 13:

The Christian must not retaliate. It is very difficult not to do so, and more difficult for some of us than others. But our Lord did not do so, and we who are His followers are to be like Him. So we must 'stay the angry word'; we must not reply. To retaliate is just to be like the natural man who always does reply; by nature he has the instinct of self-preservation and the desire to get his own back. But the Christian is different, different in nature; so he must not do that.

Furthermore, not only must he not retaliate; he must also not feel resentment. That is much more difficult. the 1st thing you do is to control your actions, the actual reply. But our Lord is not content with that, because to be truly Christian is not simply to live in a state of repression. You have to go beyond that; you have to get into the state in which you do not even resent persecution. I think you will all know from experience the difference between these two things. we may have come to see long ago that to loose our temper over a thing, or to manifest annoyance, is dishonoring our Lord. But we still may feel it, and fill it intensely, and be hurt about it and resent it bitterly. Now the Christian teaching is that we must get beyond that.