This Quran verse provides hopes to believers to not lose hope in the mercy of Allah even if they have committed sins.
Say: “O ‘Ibadi (My slaves) who have transgressed against themselves (by committing evil deeds and sins)! Despair not of the Mercy of Allah: verily, Allah forgives all sins. Truly He is Oft-Forgiving, Most Merciful.
Quran (Surah Az-Zumr, Verse 53)