Narrated Anas bin Malik:
that the Prophet (ﷺ) said: "Whoever recited Qul Huwa Allahu Ahad two hundred times everyday, fifty years worth of his sins will be removed - unless he owed a debt." (AR)
English reference (AR): Vol. 5, Book 42, Hadith 2898 (AR)
Arabic reference (AR): Book 45, Hadith 3143 (AR)