People often carelessly utter words, some of which may include or imply transgression of the limits of Islam. Such negative words may even be about Allah, or an objection to His decree, or the like, which would lead the person uttering them to the Hellfire.

For this reason, when the Prophet sallallahu 'alayhi wa sallam was talking to Mu’aath, may Allah be pleased with him, he told him: “The root (i.e. foundation) of this matter is Islam, its pillar (mainstay) is the prayer and its apex is Jihaad (fighting in the cause of Allah).” Then he sallallahu 'alayhi wa sallam asked: “Shall I tell you of that which holds together all these things?” Mu’aath, may Allah be pleased with him, said: “Yes, O Messenger of Allah!” So he sallallahu 'alayhi wa sallam held his tongue between his fingers, and said: “Restrain this.” Mu’aath, may Allah be pleased with him, asked: “O Messenger of Allah! Will we really be held to account for what we say?” The Prophet sallallahu 'alayhi wa sallam exclaimed: “May your mother lose you! Most people will be thrown on their faces into the Hellfire on account of their tongues.” [Ahmad & At-Tirmithi] The phrase: “May your mother lose you” is certainly not a supplication or a wish, as the Prophet sallallahu 'alayhi wa sallam would never have supplicated against any of his companions, but rather it is an idiom used by the Arabs to draw people's attention to the importance of what follows it, which in this case was to highlight that misuse of the tongue is the basis for the punishment of most people.

Statements from the Salaf regarding controlling and guarding the tongue: There are many statements that came in this regard, such as the words of Ibn Mas’ood, may Allah be pleased with him: “That which requires imprisonment the most is one's tongue.” [End of quote] This is why many scholars have written books about the excellence of remaining silent.