Reading Fatiha is a Pillar in the prayer for every Rak’aah.
There is no prayer for the one who does not recite the Fatiha (Bukhari)
Do not recite behind me except Fatiha (Musnad Ahmad)
[Taken from the lessons on “Conditions, Pillars and Obligation of Salah – Shaykh ul Islaam Muhammad bin Abdil Wahhab رحمه الله Explanation by Shaykh Abdul Muhsin al abbaad حفظه الله Taught by: Abdulilah Lahmami]