'Abdullah ibne-'Amr Radiyallahu 'anhuma narrates that Rasullullah Sallallahu 'alaihi wasallam said: He who recites the complete Qur'an in less than three days, cannot understand it well. (Abu Dawud: 1394)
Note: This saying of Rasullullah Sallallahu 'alaihi wasallam is for
the common Muslims, as it has been confirmed that some of the Sahabah
Radiyallahu 'anhum completed the recitation of the Qur'an in even less
than three days.