How can "those who suppress their rage" be achieved without suffering psychological harm over time, and how can this be reconciled with self-defense, and what books or articles can be read to enhance this understanding?

"Kazm al-ghaiz" (suppressing anger) is the act of restraining anger and not letting it show on one's limbs. This is achieved by overcoming and striving against the self, for "indeed, forbearance is attained through striving for forbearance."

As for combining it with self-defense, "for every occasion there is an appropriate discourse." In some situations, defending oneself is better, while in others, forgiveness is more appropriate. Forgiveness is praiseworthy when one has the ability to retaliate. Al-Tahir ibn Ashour mentioned that victory (over an aggressor) is praiseworthy for repelling injustice, and it does not contradict forgiveness, due to the difference in the contexts of the two actions.