From the teachings of St. Seraphim of Sarov
One must by every means strive to preserve peace of soul and not to be disturbed by offenses from others; for this one must in every way strive to restrain anger and by means of attentiveness to keep the mind and heart from improper feelings.
And therefore we must bear offenses from others with equanimity and accustom ourselves to such a disposition of spirit that these offenses seem to concern not us, but others.
Such a practice can give quietness to the human heart and make it a dwelling for God Himself.
An example of such angerlessness we see in St. Gregory the Wonderworker, from whom a certain prostitute in a public place asked recompense, as if for a sin he had committed with her; and he, not becoming in the least angry with her, meekly said to a certain friend of his: give her quickly the sum she demands. The woman had no sooner taken the unjust recompense than she was subjected to the attack of a demon; and the Saint drove the demon out of her by prayer.
If, however, it is impossible not to be disturbed, then at least one must strive to restrain the tongue, according to the Psalmist: I was troubled, and spoke not (Psalm 76:4 LXX).