Mishkat al-Masabih #829

Shaqiq said that Hudhaifa saw a man who was not performing the bowing or the prostration perfectly, so when he finished his prayer he called him. Hudhaifa said to him, “You have not prayed.” He added that he thought he also said, “If you were to die, you would die following something other than the true religion which God created Muhammad to proclaim.” Bukhari transmitted it.