It is narrated from Sayyiduna Abu Umamah al-Bahili (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Reticence in speech and modesty are two branches of faith, and obscene speech and harshness are two branches of hypocrisy." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it. It has an authentic supporting narration (shahid) on the condition of both of them:

It is narrated from Sayyiduna Abu Bakrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Modesty is part of faith, and (the person of) faith will be in Paradise; obscene speech is part of harshness, and (the person of) harshness will be in the Fire." It has a second supporting narration on the condition of Muslim:

It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Modesty is part of faith, and faith leads to Paradise; obscene speech is part of harshness, and harshness leads to the Fire."