The Messenger of Allah said: "Every Khutbah that does not have the Tashah-hud in it, then it is like a severed hand." (Using translation from Tirmidhī 1106)
قَالَ رَسُولُ اللَّهِ «كُلُّ خِطْبَةٍ لَيْسَ فِيهَا تَشَهَّدٌ فَهِيَ كَالْيَدِ الْجَذْمَاءِ»