Is it permissible to complete the Quran recitation in less than seven days?
Chapter on the Times When Prayer is Prohibited
Al-Mughni
Book of Prayer
Primary text
Reciting the Quran in three days is commendable, as Abdullah ibn Amr was permitted by the Prophet, peace be upon him, to recite it in three days when he stated he possessed strength. However, reciting it in less than three days is disliked according to Abu Abdullah (Ahmad ibn Hanbal), based on the narration that whoever reads it in less than three will not comprehend it.
Supporting text
There is an opposing view attributed to Ahmad where he stated that the duration is not fixed and depends on the individual's energy and strength, citing that Uthman used to complete it in one night, and this was narrated from a group of the Salaf (early Muslims).