Ahmad ibn Hanbal rahimahullah said:

“the most I have heard about completing the Quran is forty days”

This is because delaying it more than that causes forgetfulness of the Quran and taking it lackadaisical. So what we mentioned is more correct and this is if he does not have an-excuse. As for if he has an excuse, there is room/space for him’.

[al-Mughni (1/459)]