It often happens that someone sees himself sitting peacefully and quietly, but when his brother says a word that upsets him, he is troubled. Thus, he thinks that he is justly upset with him, saying, 'If he hadn't come and spoken to me and troubled me, I wouldn't have sinned.' But this is folly and absurdity. Did the person that spoke to him give him that passion? He simply showed him that the passion existed within him, so that, if he wanted to, he could repent of it. He is like fine bread bread that shines on the outside, but when one breaks it, he see its moldeness. In just the same way, he was sitting, as he thought, in peace, but he had this passion inside him he was unaware of. His brother said one word and revealed the filth hidden inside him. Therefore if he wants to receive mercy, he must repent, purify himself, progress and he must understand that he ought to thank his brother for being the great cause of his spiritual benefit.
Source: Daily Lives, Miracles, and Wisdom of the Saints and Fasting Calendar
Contributed by: boyznamedsue