The Prophet ﷺ said, "Every sermon that does not contain the testimony of faith is like a severed hand."
حدثنا مسدد وموسى بن إسمعيل قالا حدثنا عبد الواحد بن زياد حدثنا عاصم بن كليب عن أبيه
عن النبي ﷺ قال كل خطبة ليس فيها تشهد فهي كاليد الجذماء
[Its isnad is sahih] Tirmidhi narrated it, in the chapter on marriage, in the section on what has been said about the marriage sermon, no. 1106, from the hadith of Asim bin Kulayb, with this wording, and he said, hasan sahih gharib, and Ibn Hibban graded it sahih, no. 1994, and no. 579.