梵網經菩薩戒本疏 5.67

5.67

First, the rationale for establishment: 1. In order to protect the earlier three major precepts against speaking of [faults], slandering, and reviling; 2. In order to avoid distressing and troubling good people; 3. In order to protect the Buddha-Dharma and keep it free from ugliness—even the truth should not be spoken of, how much less giving rise to slander? 4. In order to avoid personally incurring the fault of heavy karma.