Abu Dawud
Prayer
Book Number: 002 / Hadith Number: 1385
Narated By Abdullah ibn Amr ibn al-'As : Yazid ibn Abdullah said that Abdullah ibn Amr asked the Prophet (pbuh): In how many days should I complete the recitation of the whole Qur'an, Apostle of Allah?
He replied: In one month.
He said: I am more energetic to complete it in a period less than this. He kept on repeating these words and lessening the period until he said: Complete its recitation in seven days.
He again said: I am more energetic to complete it in a period less than this.
The Prophet (pbuh) said: He who finishes the recitation of the Qur'an in less than three days does not understand it.