Is any one of you incapable of reciting a third of the Qur'an in a night? They (the Companions) asked: How could one recite a third of the Qur'an (in a night)? Upon this he (the Holy Prophet) said: "'Say: He is Allah, One' (Qur'an. cxii) is equivalent to a third of the Qur'an."
عَنِ النَّبِيِّ ﷺ قَالَ أَيَعْجِزُ أَحَدُكُمْ أَنْ يَقْرَأَ فِي لَيْلَةٍ ثُلُثَ الْقُرْآنِ قَالُوا وَكَيْفَ يَقْرَأْ ثُلُثَ الْقُرْآنِ ؟ قَالَ قُلْ هُوَ اللَّهُ أَحَدٌ تَعْدِلُ ثُلُثَ الْقُرْآنِ