Unforgiving towards others is a derivative of arrogance. It destroys body and soul, for the life of an impatient person is no life. It causes animosity, strife, discord, slander and many other such evils. When a person is unforgiving, Heaven is unforgiving towards him. Conversely, when a person is patient with others, Heaven is forgiving of him as well. Now, it is true that the trait of impatience is part of a person’s temperament, and that a forgiving nature is a gift of God — which is true of all negative and forbidden traits — but it is also true that man can control his spirit. By exercising daily one’s thoughts on pure thoughts and by dwelling on ethical works, a person is capable of transforming his traits from bad to good and to steer clear of death-traps, to guard the path of life instead.
One must especially be careful to not be impatient with his wife, servants and household. The Evil Inclination attempts doubly hard to incite the person towards anger, impatience and lack of forgiveness when they disobey his will. But a God-fearing Jew will subdue his heart and think: Am I not also a mortal just like my servant? And if I am fortunate that Hashem graced me with wealth and honor — it is still possible that to Hashem the servant is held in higher esteem. And if someone is obliged to treat me with honor because he or she received some benefit from me or because Hashem ordained that they honor me, then all the more so am I obligated to honor my Creator who favored me so and bestowed innumerable acts of kindness upon me. For I have acted in ways that should anger Him, and I fall so short of my duties towards Him. Woe to me if He should make me pay for my iniquity. Now, it is known that a person is treated with the same measure that he himself has used. So, if a person is impatient and unforgiving of his servants when they fail to obey him, then Hashem, as well, will be unforgiving of him for flouting His will. These sorts of thoughts are what one should take to heart and develop daily. He will then turn to Hashem and he will be healed.