Al-Kāfi

Hadith 387
silence
17ـ وَبِهَذَا الإسْنَادِ قَالَ قَالَ رَسُولُ الله (صَلَّى اللهُ عَلَيْهِ وآلِه) إِنْ كَانَ فِي شَيْ‏ءٍ شُؤْمٌ فَفِي اللِّسَانِ.
17. Through the same chain of narrators it is narrated from the Messenger of Allah (a.s.) has said, the following: “The Messenger of Allah (a.s.) has said, ‘If there is any wickedness, it is in the tongue.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī