Prayer (Kitab Al-Salat): Detailed Injunctions about Witr
Dawud :: Book 8 : Hadith 1469
Narrated Sa'd ibn Ubadah:
The Prophet (peace_be_upon_him) said: No man recites the Qur'an, then forgets it, but will meet Allah on the Day of Judgment in a maimed condition (or empty-handed, or with no excuse).