(45) باب فَضْلِ قِرَاءَةِ { قُلْ هُوَ اللَّهُ أَحَدٌ}
Abu Darda' reported Allah's Apostle (ﷺ) as saying:
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."
Reference: Sahih Muslim 811 a
In-book reference: Book 6, Hadith 314
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1769