In a conversation among R. Israel Salanter's disciples, the discussion turned to saintly individuals whose influence extends on high. One of the disciples told about a certain tzaddik who had been offended by the remarks some individuals had directed at him. The tzaddik retorted sharply and cursed them. The curse was fulfilled to the letter. R. Israel was not surprised by the incident itself, but observed in his own telling style: "Someone who had reached so elevated a stature that his words can take effect, should exercise the utmost caution to guard his tongue and lips, so as not to utter anything evil, since he can easily become a damaging agent, for what difference does it make whether one damages with his hands or with the whiplash of his tongue, smiting his neighbor in secret with the force of a Heavenly decree?" —From The Mussar Movement, Volume 1, part 2, page 212
Someone once told me that he heard his rosh yeshiva say, "The most dangerous person in the world is someone on his way to do a mitzvah." For some, nothing matters but for them to do their mitzvah, no matter what.
One of his disciples had invited him for Friday night dinner. R. Israel[Salanter] had stipulated that he would not dine anywhere till he had satisfied himself that the kashrut was above reproach. The disciple informed R. Israel that in his home all the Halachot were observed with utmost stringency. He bought his meat from a butcher known for his piety. It was truly "glatt" - free of any Halachic query or lung adhesion (sirchah). His cook was an honest woman, the widow of a Talmid Chacham, daughter of a good family, while his own wife would enter the kitchen periodically to supervise. His Friday night meal was conducted in the grand style. There would be Torah discussion after each course, so there was no possibility of their meal being "as if they had partaken of offerings to idols." They would study Shulchan Aruch regularly, sing zemirot and remain seated at the table till well into the night.
Having listened to this elaborate account of the procedures, R. Israel consented to accept the invitation, but stipulated that the time of the meal be curtailed by two full hours. Having no alternative, the disciple agreed. At the meal, one course followed another without interruption. In less than an hour, the mayim acharonim had been passed around in preparation for the Grace after Meals.
Before proceeding with the Grace, the host turned to R. Israel and asked: "Teach me, Rabbi. What defect did you notice in my table?"
R. Israel did not answer the question. Instead he asked that the widow responsible for the cooking come to the room. He said to her: "Please forgive me, for having inconvenienced you this evening. You were forced to serve one course after another - not as you are used to do."
"Bless you, Rabbi," the woman answered. "Would that you would be a guest here every Friday evening. My master is used to sit at the table till late at night. I am worn out from working all day. My legs can hardly hold me up, so tired do I become. Thanks to you, Rabbi, they hurried this evening, and I am already free to go home and rest."
R. Israel turned to his disciple. "The poor widow's remark is the answer to your question. Indeed your behavior is excellent, but only as long as it does not adversely affect others."1
--The Mussar Movement, Volume I, Part 2 pages 226-228
A person running to do a mitzvah can destroy the world on his way. -- Rabbi Yisrael Salanter
Perhaps one of the hardest things to attain is righteousness. We strive to pursue that which will bring heaven on earth; yet at the same time, we sometimes disregard those around us or hurt our fellow man in the process. How is this righteousness? The mere truth is that it isn't.
Rabbi Salanter was washing his hands before a meal when the rabbis he was with noticed he was not immersing his whole hands in water in the ritual manner preferred by Jewish law. When questioned about this practice, Rabbi Salanter responded:
“I am not the one who obtains the water from the well; it is the poor peasant girl who must do so. Several times a week in the middle of this bitter winter, she must trudge out to the well, break the ice, and bring back pails of water for us to use in our home. The more water I use to wash my hands, the more often she has to face the bitter cold. And I do not want to be extra pious on the shoulders of her suffering.”