I did not see any ayah more beautiful...

‘Ali ibn Abu Talib, radiyallahu ‘anhu, said,“I recited the Qur’an from its beginning to its end and I did not see any ayah more beautiful and full of hope than His Saying, exalted be He:

“Say, ‘O My slaves who have transgressed against themselves, do not despair of the Mercy of Allah; indeed, Allah forgives all sins. Indeed, He is the Most Forgiving, the Most Merciful.’”
Surah Az-Zumar verse 53

*Narrated by Imam Al-Qurtubi in his tafsir.