When iron strikes against stone, or fire fights with water, or the Kshatriya stands against the Brahmana, then the strength of each of those three is destroyed.
यदा छिनत्त्ययोऽश्मानग्निश्चापोऽभिगच्छति। क्षत्रं च ब्राह्मणं द्वेशि तदा नश्यन्ति ते त्रयः॥