A yogi is much more disciplined in his speech. Yogic tradition has it that speech must pass before three barriers prior to being uttered aloud. These barriers come in the form of three questions: Is it kind? Is it true? Is it necessary? (112-113)
Prem Prakash, The Yoga of Spiritual Devotion A Modern Translation of the Narada Bhakti Sutras
honesty, kindness, necessity, right-speech, speech