Narrated Aisha:
The Prophet (ﷺ) said, "Such a person as recites the Qur'an and masters it by heart, will be with the noble righteous scribes (in Heaven). And such a person exerts himself to learn the Qur'an by heart, and recites it with great difficulty, will have a double reward."
USC-MSA web (English) reference: Vol. 6, Book 60, Hadith 459
Arabic reference: Book 65, Hadith 4937