Narrated ‘Abdullah bin ‘Amr:
Allah’s Apostle said to me, “Recite the whole Qur’an in one month’s time.” I said, “But I have power (to do more than that).” Allah’s Apostle said, “Then finish the recitation of the Qur’an in seven days, and do not finish it in less than this period.”
Sahih Bukhari, Volume 6, Book61, Number 574