Sayyiduna Ali (may Allah be pleased with him) says: The Messenger of Allah (peace and blessings be upon him and his family) forbade that a person recite (Qur'an) while in bowing (ruku') or prostration (sajdah).

Aman bin Saad says that a man asked Sayyiduna Ali (may Allah be pleased with him): "Can I recite (Qur'an) in bowing and prostration?" He replied: The Messenger of Allah (peace and blessings be upon him) said: I have been forbidden from reciting (Qur'an) in bowing and prostration. When you bow, then glorify the greatness of Allah, and when you prostrate, then strive to supplicate, for it is more likely that it will be accepted for you.

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Beware! Indeed, I have been forbidden from reciting (Qur'an) during bowing and prostration, therefore, in bowing, glorify your Lord, the Exalted, and in prostration, strive in supplication, for it is most likely that it will be accepted for you.