Narrated by Sayyiduna Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Every sermon in which there is no testimony is like a severed hand.
Hadith Takhrij«اسناده قوي، أخرجه ابوداود: 4841، والترمذي: 1106 ، (انظر مسند أحمد ترقيم الرسالة: 8518 ترقیم بيت الأفكار الدولية: 8499»
Brief Explanation
Benefits: … By "testimony" (shahadah) is meant: "Ashhadu an la ilaha illallah wa ashhadu anna Muhammadan abduhu wa rasuluhu" (I bear witness that there is no deity except Allah, and I bear witness that Muhammad is His servant and Messenger).
Just as a severed hand has no benefit, similarly, a sermon (khutbah) is of no benefit to the preacher if it does not contain the testimony to the Oneness of Allah (tawhid) and the Messengership (risalah) of Muhammad.