Muhammad ibn Ya‘qub, from Muhammad ibn Yahya, from Ahmad ibn Muhammad, from Ali ibn al-Hakam, from Uthman ibn Abd al-Malik, from Abu Bakr al-Hadrami, who said: Abu Ja‘far عليه السلام said: "Do you know what defines the bowing and the prostration?" I (al-Hadrami) said: “No.” Imam عليه السلام said: "Say in the bowing three times: ‘Subhana rabbiyal-‘azim wa bihamdih’, and in the prostration: ‘Subhana rabbiyal-a‘la wa bihamdih’ three times. Whoever leaves out one (recitation) has left out one-third of his prayer, and whoever leaves out two has left out two-thirds of his prayer, and whoever does not recite the tasbih at all, he has no prayer."