Musannaf Ibn Abi Shaybah

Hazrat Hamla bin Abdur Rahman narrates that Hazrat Ubadah saw a man who was not performing ruku and sujood properly. He took hold of that man's hand, so the man became frightened. Hazrat Ubadah said, "Do not imitate him or those like him. And remember that there is no prayer without Surah Al-Fatiha."