"This is a great lesson for us all to learn, that in all matters the two extremes are alike. The extreme positive and the extreme negative are always similar. When the vibrations of light are too slow, we do not see them, nor do we see them when they are too rapid. So with sound; when very low in pitch, we do not hear it; when very high, we do not hear it either. Of like nature is the difference between resistance and non-resistance. One man does not resist because he is weak, lazy, and cannot, not because he will not; the other man knows that he can strike an irresistible blow if he likes; yet he not only does not strike, but blesses his enemies. The one who from weakness resists not commits a sin, and as such cannot receive any benefit from the non-resistance; while the other would commit a sin by offering resistance."

- Swami Vivekananda, "Each Is Great in His Own Place" (Advanced karma yoga class, Dec 13, 1895, New York Vedanta Society), Karma Yoga, Complete Works: Vol 1