Tertullian On Prayer , for prayer's sake "at the sixth hour."[169] Tertullian On Fasting had, for the sake of taking food, gone up first on the roof to pray;[77] Origen Against Celsus Book II And the voice spake unto him again the second time, What God hath cleansed, that call thou not common."[4] Didache 3. Thrice in the day thus pray.[85] The Teaching of the Apostles the inquiries:[8] strange tongues[9]