" According to a hadith, the tongue is the “interpreter of the heart.” Hypocrisy is wretched because the hypocrite says with his tongue what is not in his heart. He wrongs his tongue and oppresses his heart. But if the heart is sound, the condition of the tongue follows suit. We are commanded to be upright in our speech, which is a gauge of the heart’s state. According to a prophetic tradition, each morning, when the limbs and organs awaken in the spiritual world, they shudder and say to the tongue, “Fear God concerning us! For if you are upright, then we are upright; and if you deviate, we too deviate.” Engaging in the regular remembrance of God (dhikr) safeguards the tongue and replaces idle talk with words and phrases that raise one in honor. The tongue is essential in developing courtesy with God, which is the whole point of existence. "

― Hamza Yusuf , Purification of the Heart: Signs, Symptoms and Cures of the Spiritual Diseases of the Heart