عَنْ عَلِيٍّ رَضِيَ اللَّهُ عَنْهُ قَالَ: نَهَى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ أَنْ يَقْرَأَ الرَّجُلُ وَهُوَ رَاكِعٌ أَوْ سَاجِدٌ
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).